diff --git a/Sources/geometrize-cli/main.swift b/Sources/geometrize-cli/main.swift
index 90016fa..a1ddd9c 100644
--- a/Sources/geometrize-cli/main.swift
+++ b/Sources/geometrize-cli/main.swift
@@ -12,8 +12,6 @@ struct GeometrizeOptions: ParsableArguments {
     @Flag(name: .shortAndLong, help: "Verbose output.") var verbose: Bool = false
 }
 
-//print("Available shaped: \(ShapeType.allCases.map(\.rawValueCapitalized).joined(by: ", ")).")
-
 let options = GeometrizeOptions.parseOrExit()
 
 let inputUrl = URL(fileURLWithPath: options.inputPath)
@@ -65,25 +63,35 @@ guard outputUrl.pathExtension.caseInsensitiveCompare("svg") == .orderedSame else
 }
 
 // TODO: use ExpressibleByArgument?
-let shapeTypes = options.shapeTypes.components(separatedBy: .whitespacesAndNewlines)
-let shapesOrNil = shapeTypes.map(ShapeType.init)
-let indexOfNil = shapesOrNil.firstIndex(of: nil)
-if let indexOfNil = indexOfNil {
-    print("Not recognised shape type \(shapeTypes[indexOfNil]). Allowed shape types:")
-    ShapeType.allCases.forEach {
-        print($0.rawValueCapitalized)
+let shapes = options.shapeTypes.components(separatedBy: .whitespacesAndNewlines).shapeTypes()
+
+// Shape.Type is not hashable as all Metatypes. Why, by the way?
+// That why we check for nil in this strange way.
+var indexOfNil: Int?
+for (i, shape) in shapes.enumerated() {
+    if shape == nil {
+        indexOfNil = i
+        break
+    }
+}
+
+if let indexOfNil {
+    print("Not recognised shape type \(shapes[indexOfNil]!). Allowed shape types:")
+    allShapeTypes.forEach {
+        print("\($0)")
     }
     print("Case insensitive, underscores are ignored, white spaces are delimiters.")
     exit(1)
 }
 
-let shapes = Set(shapesOrNil.compactMap { $0 })
-print("Using shapes: \(shapes.map(\.rawValueCapitalized).joined(separator: ", ")).")
+let shapeTypes: [Shape.Type] = shapes.compactMap { $0 }
+
+print("Using shapes: \(shapeTypes.map { "\(type(of: $0))".dropLast(5) /* drop .Type */ }.joined(separator: ", ")).")
 
 let shapeCount: Int = Int(options.shapeCount ?? 100)
 
 let runnerOptions = ImageRunnerOptions(
-    shapeTypes: shapes,
+    shapeTypes: shapeTypes,
     alpha: 128,
     shapeCount: 100,
     maxShapeMutations: 100,
diff --git a/Sources/geometrize/ImageRunner.swift b/Sources/geometrize/ImageRunner.swift
index 3bd69cf..022a6ce 100644
--- a/Sources/geometrize/ImageRunner.swift
+++ b/Sources/geometrize/ImageRunner.swift
@@ -32,7 +32,7 @@ public struct ImageRunnerShapeBoundsOptions {
 public struct ImageRunnerOptions {
 
     /// The shape types that the image runner shall use.
-    var shapeTypes: Set<ShapeType>
+    var shapeTypes: [Shape.Type]
 
     /// The alpha/opacity of the shapes (0-255).
     var alpha: UInt8
@@ -53,7 +53,7 @@ public struct ImageRunnerOptions {
     /// If zero or do not form a rectangle, the entire target image is used i.e. (0, 0, imageWidth, imageHeight).
     var shapeBounds: ImageRunnerShapeBoundsOptions
 
-    public init(shapeTypes: Set<ShapeType>, alpha: UInt8, shapeCount: Int, maxShapeMutations: Int, seed: Int, maxThreads: Int, shapeBounds: ImageRunnerShapeBoundsOptions) {
+    public init(shapeTypes: [Shape.Type], alpha: UInt8, shapeCount: Int, maxShapeMutations: Int, seed: Int, maxThreads: Int, shapeBounds: ImageRunnerShapeBoundsOptions) {
         self.shapeTypes = shapeTypes
         self.alpha = alpha
         self.shapeCount = shapeCount
diff --git a/Sources/geometrize/SVGExporter.swift b/Sources/geometrize/SVGExporter.swift
index cc30725..df3d3f8 100644
--- a/Sources/geometrize/SVGExporter.swift
+++ b/Sources/geometrize/SVGExporter.swift
@@ -35,11 +35,10 @@ public struct SVGExporter {
     /// - Returns: The SVG shape data for the given shape
     func singleShapeData(color: Rgba, shape: any Shape, options: ExportOptions = ExportOptions()) -> String {
         var shapeData: String = shapeData(shape: shape, options: options)
-        let shapeType = shape.type()
 
         var styles: String = "id=\"\(options.itemId)\" "
 
-        if [ShapeType.line, ShapeType.polyline, ShapeType.quadraticBezier].contains(shapeType) {
+        if shape.self is Line || shape.self is Polyline || shape.self is QuadraticBezier {
             styles += strokeAttrib(color: color)
             styles += " stroke-width=\"1\" fill=\"none\" "
             styles += strokeOpacityAttrib(color: color)
diff --git a/Sources/geometrize/Scanline.swift b/Sources/geometrize/Scanline.swift
index 955a1b7..4b21da7 100644
--- a/Sources/geometrize/Scanline.swift
+++ b/Sources/geometrize/Scanline.swift
@@ -20,7 +20,7 @@ public struct Scanline {
         self.x1 = x1
         self.x2 = x2
         if x1 > x2 {
-            print("Warning: Scanline has x1(\(x1)) > x2(\(x2). This makes scanline invisible..")
+            print("Warning: Scanline has x1(\(x1)) > x2(\(x2). This makes scanline invisible.")
         }
     }
 
diff --git a/Sources/geometrize/ShapeCreator.swift b/Sources/geometrize/ShapeCreator.swift
index dda6073..cb355ef 100644
--- a/Sources/geometrize/ShapeCreator.swift
+++ b/Sources/geometrize/ShapeCreator.swift
@@ -6,20 +6,13 @@ public typealias ShapeCreator = (inout SplitMix64) -> any Shape
 /// - Parameters:
 ///   - types: The types of shapes to create.
 /// - Returns: The default shape creator.
-public func makeDefaultShapeCreator(types: Set<ShapeType>) -> ShapeCreator {
+public func makeDefaultShapeCreator(types: [Shape.Type]) -> ShapeCreator {
     return { generator in
-        let shape: Shape
-        switch types[types.index(types.startIndex, offsetBy: Int._random(in: 0...types.count - 1, using: &generator))] {
-        case .rectangle: shape = Rectangle()
-        case .rotatedRectangle: shape = RotatedRectangle()
-        case .rotatedEllipse: shape = RotatedEllipse()
-        case .triangle: shape = Triangle()
-        case .circle: shape = Circle()
-        case .ellipse: shape = Ellipse()
-        case .line: shape = Line()
-        case .polyline: shape = Polyline()
-        case .quadraticBezier: shape = QuadraticBezier()
-        }
-        return shape
+        let index = types.index(
+            types.startIndex,
+            offsetBy: Int._random(in: 0...types.count - 1, using: &generator)
+        )
+        let shapeType = types[index]
+        return shapeType.init()
     }
 }
diff --git a/Sources/geometrize/Shapes/Bounds.swift b/Sources/geometrize/Shapes/Bounds.swift
new file mode 100644
index 0000000..8bba72c
--- /dev/null
+++ b/Sources/geometrize/Shapes/Bounds.swift
@@ -0,0 +1,16 @@
+import Foundation
+
+public struct Bounds {
+    let xMin: Int
+    let xMax: Int
+    let yMin: Int
+    let yMax: Int
+
+    public init(xMin: Int, xMax: Int, yMin: Int, yMax: Int) {
+        self.xMin = xMin
+        self.xMax = xMax
+        self.yMin = yMin
+        self.yMax = yMax
+    }
+}
+
diff --git a/Sources/geometrize/Shapes/Circle.swift b/Sources/geometrize/Shapes/Circle.swift
index abe2527..fb9c735 100644
--- a/Sources/geometrize/Shapes/Circle.swift
+++ b/Sources/geometrize/Shapes/Circle.swift
@@ -67,10 +67,6 @@ public final class Circle: Shape {
         return lines
     }
 
-    public func type() -> ShapeType {
-        .circle
-    }
-
     public var isDegenerate: Bool {
         r == 0.0
     }
diff --git a/Sources/geometrize/Shapes/Ellipse.swift b/Sources/geometrize/Shapes/Ellipse.swift
index ecaabf0..d7ea774 100644
--- a/Sources/geometrize/Shapes/Ellipse.swift
+++ b/Sources/geometrize/Shapes/Ellipse.swift
@@ -81,10 +81,6 @@ public final class Ellipse: Shape {
         return lines
     }
 
-    public func type() -> ShapeType {
-        .ellipse
-    }
-
     public var isDegenerate: Bool {
         rx == 0.0 || ry == 0.0
     }
diff --git a/Sources/geometrize/Shapes/Line.swift b/Sources/geometrize/Shapes/Line.swift
index 77361cd..8a821bf 100644
--- a/Sources/geometrize/Shapes/Line.swift
+++ b/Sources/geometrize/Shapes/Line.swift
@@ -64,10 +64,6 @@ public final class Line: Shape {
         return lines
     }
 
-    public func type() -> ShapeType {
-        .line
-    }
-
     public var isDegenerate: Bool {
         x1 == x2 && y1 == y2
     }
diff --git a/Sources/geometrize/Shapes/Polyline.swift b/Sources/geometrize/Shapes/Polyline.swift
index 50842bb..2e0f737 100644
--- a/Sources/geometrize/Shapes/Polyline.swift
+++ b/Sources/geometrize/Shapes/Polyline.swift
@@ -67,10 +67,6 @@ public final class Polyline: Shape {
         return lines
     }
 
-    public func type() -> ShapeType {
-        .polyline
-    }
-
     public var description: String {
         "Polyline(" + points.map(\.description).joined(separator: ", ") + ")"
     }
diff --git a/Sources/geometrize/Shapes/QuadraticBezier.swift b/Sources/geometrize/Shapes/QuadraticBezier.swift
index 4452c08..34dd099 100644
--- a/Sources/geometrize/Shapes/QuadraticBezier.swift
+++ b/Sources/geometrize/Shapes/QuadraticBezier.swift
@@ -88,10 +88,6 @@ public final class QuadraticBezier: Shape {
         return lines
     }
 
-    public func type() -> ShapeType {
-        .quadraticBezier
-    }
-
     public var description: String {
         "QuadraticBezier(cx=\(cx), cy=\(cy), x1=\(x1), y1=\(y1), x2=\(x2), y2=\(y2))"
     }
diff --git a/Sources/geometrize/Shapes/Rectangle.swift b/Sources/geometrize/Shapes/Rectangle.swift
index d2396d2..15b304e 100644
--- a/Sources/geometrize/Shapes/Rectangle.swift
+++ b/Sources/geometrize/Shapes/Rectangle.swift
@@ -80,10 +80,6 @@ public final class Rectangle: Shape {
          Point<Double>(x: x1, y: y2))
     }
 
-    public func type() -> ShapeType {
-        .rectangle
-    }
-
     public var isDegenerate: Bool {
         x1 == x2 || y1 == y2
     }
diff --git a/Sources/geometrize/Shapes/RotatedEllipse.swift b/Sources/geometrize/Shapes/RotatedEllipse.swift
index 8f06110..370f7d5 100644
--- a/Sources/geometrize/Shapes/RotatedEllipse.swift
+++ b/Sources/geometrize/Shapes/RotatedEllipse.swift
@@ -83,10 +83,6 @@ public final class RotatedEllipse: Shape {
         return points
     }
 
-    public func type() -> ShapeType {
-        .rotatedEllipse
-    }
-
     public var isDegenerate: Bool {
         rx == 0.0 || ry == 0.0
     }
diff --git a/Sources/geometrize/Shapes/RotatedRectangle.swift b/Sources/geometrize/Shapes/RotatedRectangle.swift
index 6154414..95c3604 100644
--- a/Sources/geometrize/Shapes/RotatedRectangle.swift
+++ b/Sources/geometrize/Shapes/RotatedRectangle.swift
@@ -103,10 +103,6 @@ public final class RotatedRectangle: Shape {
         return (ul, ur, br, bl)
     }
 
-    public func type() -> ShapeType {
-        .rotatedRectangle
-    }
-
     public var isDegenerate: Bool {
         x1 == x2 || y1 == y2
     }
diff --git a/Sources/geometrize/Shapes/Shape.swift b/Sources/geometrize/Shapes/Shape.swift
index aa7cdc6..26b2e68 100644
--- a/Sources/geometrize/Shapes/Shape.swift
+++ b/Sources/geometrize/Shapes/Shape.swift
@@ -1,49 +1,5 @@
 import Foundation
 
-// Specifies the types of shapes that can be used.
-// These can be combined to produce images composed of multiple primitive types.
-// TODO: put it inside Shape. Or remove completely.
-public enum ShapeType: String, CaseIterable {
-    case rectangle
-    case rotatedRectangle
-    case triangle
-    case ellipse
-    case rotatedEllipse
-    case circle
-    case line
-    case quadraticBezier
-    case polyline
-
-    public var rawValueCapitalized: String {
-        let firstUppercased = rawValue.first!.uppercased()
-        return firstUppercased + rawValue.dropFirst()
-    }
-
-    // Allows rotatedrectangle and rotated_rectangle, casing doesn't matter.
-    public init?(rawValue: String) {
-        let allCases = ShapeType.allCases
-        let all = allCases.map { $0.rawValue.lowercased() }
-        guard let index = all.firstIndex(of: rawValue.replacingOccurrences(of: "_", with: "").lowercased()) else {
-            return nil
-        }
-        self = allCases[index]
-    }
-}
-
-public struct Bounds {
-    let xMin: Int
-    let xMax: Int
-    let yMin: Int
-    let yMax: Int
-
-    public init(xMin: Int, xMax: Int, yMin: Int, yMax: Int) {
-        self.xMin = xMin
-        self.xMax = xMax
-        self.yMin = yMin
-        self.yMax = yMax
-    }
-}
-
 public protocol Shape: AnyObject, CustomStringConvertible {
     init()
 
@@ -55,8 +11,6 @@ public protocol Shape: AnyObject, CustomStringConvertible {
 
     func rasterize(xMin: Int, yMin: Int, xMax: Int, yMax: Int) -> [Scanline]
 
-    func type() -> ShapeType
-
     var isDegenerate: Bool { get }
 }
 
@@ -74,3 +28,27 @@ func == (lhs: any Shape, rhs: any Shape) -> Bool {
     default: return false
     }
 }
+
+public let allShapeTypes: [Shape.Type] = [
+    Rectangle.self,
+    RotatedRectangle.self,
+    Triangle.self,
+    Circle.self,
+    Ellipse.self,
+    RotatedEllipse.self,
+    Line.self,
+    Polyline.self,
+    QuadraticBezier.self
+]
+
+public extension Array where Element == String {
+
+    func shapeTypes() -> [Shape.Type?] {
+        let allShapeTypeStrings = allShapeTypes.map { "\(type(of: $0))".dropLast(5).lowercased() } // /* drop .Type */
+        return self.map {
+            let needle = $0.lowercased().replacingOccurrences(of: "_", with: "")
+            return allShapeTypeStrings.firstIndex(of: needle).flatMap { allShapeTypes[$0] }
+        }
+    }
+
+}
diff --git a/Sources/geometrize/Shapes/Triangle.swift b/Sources/geometrize/Shapes/Triangle.swift
index a64c162..48c331a 100644
--- a/Sources/geometrize/Shapes/Triangle.swift
+++ b/Sources/geometrize/Shapes/Triangle.swift
@@ -80,10 +80,6 @@ public final class Triangle: Shape {
         return lines
     }
 
-    public func type() -> ShapeType {
-        .triangle
-    }
-
     public var isDegenerate: Bool {
         x1 == x2 && y1 == y2 ||
         x1 == x3 && y1 == y3 ||
diff --git a/Tests/geometrizeTests/ImageRunnerTests.swift b/Tests/geometrizeTests/ImageRunnerTests.swift
index ad552b1..a03cf13 100644
--- a/Tests/geometrizeTests/ImageRunnerTests.swift
+++ b/Tests/geometrizeTests/ImageRunnerTests.swift
@@ -19,7 +19,7 @@ final class ImageRunnerTests: XCTestCase {
         let targetBitmap = Bitmap(width: width, height: height, data: data)
 
         let options = ImageRunnerOptions(
-            shapeTypes: Set([.rotatedEllipse]),
+            shapeTypes: [RotatedEllipse.self],
             alpha: 128,
             shapeCount: 500,
             maxShapeMutations: 100,
diff --git a/Tests/geometrizeTests/ShapeTypesTests.swift b/Tests/geometrizeTests/ShapeTypesTests.swift
new file mode 100644
index 0000000..33eb773
--- /dev/null
+++ b/Tests/geometrizeTests/ShapeTypesTests.swift
@@ -0,0 +1,30 @@
+import XCTest
+@testable import Geometrize
+
+final class ShapeTypesTests: XCTestCase {
+
+    func testEmpty() throws {
+        XCTAssertTrue([String]().shapeTypes().isEmpty)
+    }
+
+    func testRectangle() throws {
+        let array = ["rectangle"].shapeTypes()
+        XCTAssertEqual(array.count, 1)
+        XCTAssert(array[0]! is Rectangle.Type)
+    }
+
+    func testRotated_Rectangle() throws {
+        let array = ["Rotated_rectangle"].shapeTypes()
+        XCTAssertEqual(array.count, 1)
+        XCTAssert(array[0]! is RotatedRectangle.Type)
+    }
+
+    func testRectangleCircleGarbage() throws {
+        let array = ["Rectangle", "Circle", "bla-bla-bla"].shapeTypes()
+        XCTAssertEqual(array.count, 3)
+        XCTAssert(array[0]! is Rectangle.Type)
+        XCTAssert(array[1]! is Circle.Type)
+        XCTAssertNil(array[2])
+    }
+
+}