diff --git a/Sources/DoggieCore/Foundation/WeakDictionary.swift b/Sources/DoggieCore/Foundation/WeakDictionary.swift
index 150c746d..e8f7cf41 100644
--- a/Sources/DoggieCore/Foundation/WeakDictionary.swift
+++ b/Sources/DoggieCore/Foundation/WeakDictionary.swift
@@ -87,6 +87,16 @@ extension WeakDictionary {
     }
 }
 
+#if compiler(>=5.5.2) && canImport(_Concurrency)
+
+@available(macOS 10.15, iOS 13, tvOS 13, watchOS 6, *)
+extension WeakDictionary: Sendable where Key: Sendable, Value: Sendable { }
+
+@available(macOS 10.15, iOS 13, tvOS 13, watchOS 6, *)
+extension WeakDictionary.ValueContainer: Sendable where Key: Sendable, Value: Sendable { }
+
+#endif
+
 extension WeakDictionary {
     
     @inlinable
diff --git a/Sources/DoggieCore/Foundation/WeakSet.swift b/Sources/DoggieCore/Foundation/WeakSet.swift
index f02ce035..cf64d8b7 100644
--- a/Sources/DoggieCore/Foundation/WeakSet.swift
+++ b/Sources/DoggieCore/Foundation/WeakSet.swift
@@ -81,6 +81,16 @@ extension WeakSet {
     }
 }
 
+#if compiler(>=5.5.2) && canImport(_Concurrency)
+
+@available(macOS 10.15, iOS 13, tvOS 13, watchOS 6, *)
+extension WeakSet: Sendable where Element: Sendable { }
+
+@available(macOS 10.15, iOS 13, tvOS 13, watchOS 6, *)
+extension WeakSet.ElementContainer: Sendable where Element: Sendable { }
+
+#endif
+
 extension WeakSet {
     
     @inlinable
diff --git a/Sources/DoggieCore/Swift/OptionOneCollection.swift b/Sources/DoggieCore/Swift/OptionOneCollection.swift
index e9145534..18571b2e 100644
--- a/Sources/DoggieCore/Swift/OptionOneCollection.swift
+++ b/Sources/DoggieCore/Swift/OptionOneCollection.swift
@@ -74,6 +74,13 @@ extension OptionOneCollection: Hashable where T: Hashable {
     
 }
 
+#if compiler(>=5.5.2) && canImport(_Concurrency)
+
+@available(macOS 10.15, iOS 13, tvOS 13, watchOS 6, *)
+extension OptionOneCollection: Sendable where T: Sendable { }
+
+#endif
+
 extension OptionOneCollection: ContiguousBytes where Element == UInt8 {
     
     @inlinable
diff --git a/Sources/DoggieGeometry/Bezier/Bezier.swift b/Sources/DoggieGeometry/Bezier/Bezier.swift
index 41eb24e7..5bdf4e27 100644
--- a/Sources/DoggieGeometry/Bezier/Bezier.swift
+++ b/Sources/DoggieGeometry/Bezier/Bezier.swift
@@ -100,6 +100,13 @@ extension Bezier: Encodable where Element: Encodable {
     }
 }
 
+#if compiler(>=5.5.2) && canImport(_Concurrency)
+
+@available(macOS 10.15, iOS 13, tvOS 13, watchOS 6, *)
+extension Bezier: Sendable where Element: Sendable { }
+
+#endif
+
 extension Bezier {
     
     @inlinable
diff --git a/Sources/DoggieGeometry/Bezier/CubicBezier.swift b/Sources/DoggieGeometry/Bezier/CubicBezier.swift
index eaf6e1f2..96d34f92 100644
--- a/Sources/DoggieGeometry/Bezier/CubicBezier.swift
+++ b/Sources/DoggieGeometry/Bezier/CubicBezier.swift
@@ -89,6 +89,13 @@ extension CubicBezier: Encodable where Element: Encodable {
     }
 }
 
+#if compiler(>=5.5.2) && canImport(_Concurrency)
+
+@available(macOS 10.15, iOS 13, tvOS 13, watchOS 6, *)
+extension CubicBezier: Sendable where Element: Sendable { }
+
+#endif
+
 extension CubicBezier {
     
     @inlinable
diff --git a/Sources/DoggieGeometry/Bezier/CubicBezierPatch.swift b/Sources/DoggieGeometry/Bezier/CubicBezierPatch.swift
index 11c9a1c0..2eeab4d6 100644
--- a/Sources/DoggieGeometry/Bezier/CubicBezierPatch.swift
+++ b/Sources/DoggieGeometry/Bezier/CubicBezierPatch.swift
@@ -106,6 +106,13 @@ extension CubicBezierPatch: Hashable where Element: Hashable {
     
 }
 
+#if compiler(>=5.5.2) && canImport(_Concurrency)
+
+@available(macOS 10.15, iOS 13, tvOS 13, watchOS 6, *)
+extension CubicBezierPatch: Sendable where Element: Sendable { }
+
+#endif
+
 extension CubicBezierPatch {
     
     @inlinable
diff --git a/Sources/DoggieGeometry/Bezier/CubicBezierTriangularPatch.swift b/Sources/DoggieGeometry/Bezier/CubicBezierTriangularPatch.swift
index d9b187f8..78ee5a9b 100644
--- a/Sources/DoggieGeometry/Bezier/CubicBezierTriangularPatch.swift
+++ b/Sources/DoggieGeometry/Bezier/CubicBezierTriangularPatch.swift
@@ -60,6 +60,13 @@ extension CubicBezierTriangularPatch: Hashable where Element: Hashable {
     
 }
 
+#if compiler(>=5.5.2) && canImport(_Concurrency)
+
+@available(macOS 10.15, iOS 13, tvOS 13, watchOS 6, *)
+extension CubicBezierTriangularPatch: Sendable where Element: Sendable { }
+
+#endif
+
 extension CubicBezierTriangularPatch {
     
     @inlinable
diff --git a/Sources/DoggieGeometry/Bezier/LineSegment.swift b/Sources/DoggieGeometry/Bezier/LineSegment.swift
index 1bb6a7b8..ef583b85 100644
--- a/Sources/DoggieGeometry/Bezier/LineSegment.swift
+++ b/Sources/DoggieGeometry/Bezier/LineSegment.swift
@@ -78,6 +78,13 @@ extension LineSegment: Encodable where Element: Encodable {
     }
 }
 
+#if compiler(>=5.5.2) && canImport(_Concurrency)
+
+@available(macOS 10.15, iOS 13, tvOS 13, watchOS 6, *)
+extension LineSegment: Sendable where Element: Sendable { }
+
+#endif
+
 extension LineSegment {
     
     @inlinable
diff --git a/Sources/DoggieGeometry/Bezier/QuadBezier.swift b/Sources/DoggieGeometry/Bezier/QuadBezier.swift
index 4c81154b..f36b8c08 100644
--- a/Sources/DoggieGeometry/Bezier/QuadBezier.swift
+++ b/Sources/DoggieGeometry/Bezier/QuadBezier.swift
@@ -84,6 +84,13 @@ extension QuadBezier: Encodable where Element: Encodable {
     }
 }
 
+#if compiler(>=5.5.2) && canImport(_Concurrency)
+
+@available(macOS 10.15, iOS 13, tvOS 13, watchOS 6, *)
+extension QuadBezier: Sendable where Element: Sendable { }
+
+#endif
+
 extension QuadBezier {
     
     @inlinable
diff --git a/Sources/DoggieGeometry/Geometry/EdgeInsets.swift b/Sources/DoggieGeometry/Geometry/EdgeInsets.swift
index 965ad32c..38376eb6 100644
--- a/Sources/DoggieGeometry/Geometry/EdgeInsets.swift
+++ b/Sources/DoggieGeometry/Geometry/EdgeInsets.swift
@@ -44,6 +44,13 @@ public struct EdgeInsets: Hashable {
     }
 }
 
+#if compiler(>=5.5.2) && canImport(_Concurrency)
+
+@available(macOS 10.15, iOS 13, tvOS 13, watchOS 6, *)
+extension EdgeInsets: Sendable { }
+
+#endif
+
 extension Rect {
     
     @inlinable
diff --git a/Sources/DoggieGeometry/Geometry/Ellipse.swift b/Sources/DoggieGeometry/Geometry/Ellipse.swift
index 26a3bf36..2db77a55 100644
--- a/Sources/DoggieGeometry/Geometry/Ellipse.swift
+++ b/Sources/DoggieGeometry/Geometry/Ellipse.swift
@@ -78,6 +78,13 @@ extension Radius: Codable {
     }
 }
 
+#if compiler(>=5.5.2) && canImport(_Concurrency)
+
+@available(macOS 10.15, iOS 13, tvOS 13, watchOS 6, *)
+extension Radius: Sendable { }
+
+#endif
+
 @inlinable
 @inline(__always)
 public func Ellipse(_ t: Double, _ p: Point, _ r: Radius) -> Point {
diff --git a/Sources/DoggieGeometry/Geometry/Matrix.swift b/Sources/DoggieGeometry/Geometry/Matrix.swift
index d7d1d026..386cd7d1 100644
--- a/Sources/DoggieGeometry/Geometry/Matrix.swift
+++ b/Sources/DoggieGeometry/Geometry/Matrix.swift
@@ -129,6 +129,13 @@ extension Matrix: Codable {
     }
 }
 
+#if compiler(>=5.5.2) && canImport(_Concurrency)
+
+@available(macOS 10.15, iOS 13, tvOS 13, watchOS 6, *)
+extension Matrix: Sendable { }
+
+#endif
+
 extension Matrix {
     
     @inlinable
diff --git a/Sources/DoggieGeometry/Geometry/Point.swift b/Sources/DoggieGeometry/Geometry/Point.swift
index b422ba43..e31ed1d4 100644
--- a/Sources/DoggieGeometry/Geometry/Point.swift
+++ b/Sources/DoggieGeometry/Geometry/Point.swift
@@ -131,6 +131,13 @@ extension Point: Codable {
     }
 }
 
+#if compiler(>=5.5.2) && canImport(_Concurrency)
+
+@available(macOS 10.15, iOS 13, tvOS 13, watchOS 6, *)
+extension Point: Sendable { }
+
+#endif
+
 extension Point: Tensor {
     
     public typealias Indices = Range<Int>
diff --git a/Sources/DoggieGeometry/Geometry/Rect.swift b/Sources/DoggieGeometry/Geometry/Rect.swift
index 26044ac1..af626c44 100644
--- a/Sources/DoggieGeometry/Geometry/Rect.swift
+++ b/Sources/DoggieGeometry/Geometry/Rect.swift
@@ -98,6 +98,13 @@ extension Rect: Codable {
     }
 }
 
+#if compiler(>=5.5.2) && canImport(_Concurrency)
+
+@available(macOS 10.15, iOS 13, tvOS 13, watchOS 6, *)
+extension Rect: Sendable { }
+
+#endif
+
 extension Rect {
     
     @inlinable
diff --git a/Sources/DoggieGeometry/Geometry/SDTransform.swift b/Sources/DoggieGeometry/Geometry/SDTransform.swift
index 04ee4cb7..bac7ee2e 100644
--- a/Sources/DoggieGeometry/Geometry/SDTransform.swift
+++ b/Sources/DoggieGeometry/Geometry/SDTransform.swift
@@ -98,6 +98,13 @@ extension SDTransform: Codable {
     }
 }
 
+#if compiler(>=5.5.2) && canImport(_Concurrency)
+
+@available(macOS 10.15, iOS 13, tvOS 13, watchOS 6, *)
+extension SDTransform: Sendable { }
+
+#endif
+
 extension SDTransform {
     
     @inlinable
diff --git a/Sources/DoggieGeometry/Geometry/Size.swift b/Sources/DoggieGeometry/Geometry/Size.swift
index 950be42c..3fbb29c5 100644
--- a/Sources/DoggieGeometry/Geometry/Size.swift
+++ b/Sources/DoggieGeometry/Geometry/Size.swift
@@ -90,6 +90,13 @@ extension Size: Codable {
     }
 }
 
+#if compiler(>=5.5.2) && canImport(_Concurrency)
+
+@available(macOS 10.15, iOS 13, tvOS 13, watchOS 6, *)
+extension Size: Sendable { }
+
+#endif
+
 extension Size {
     
     @inlinable
diff --git a/Sources/DoggieGeometry/Geometry/Vector.swift b/Sources/DoggieGeometry/Geometry/Vector.swift
index 26f57bd6..b6837f0e 100644
--- a/Sources/DoggieGeometry/Geometry/Vector.swift
+++ b/Sources/DoggieGeometry/Geometry/Vector.swift
@@ -114,6 +114,13 @@ extension Vector: Codable {
     }
 }
 
+#if compiler(>=5.5.2) && canImport(_Concurrency)
+
+@available(macOS 10.15, iOS 13, tvOS 13, watchOS 6, *)
+extension Vector: Sendable { }
+
+#endif
+
 extension Vector {
     
     @inlinable
diff --git a/Sources/DoggieMath/Complex.swift b/Sources/DoggieMath/Complex.swift
index 5a2b235f..9126becb 100644
--- a/Sources/DoggieMath/Complex.swift
+++ b/Sources/DoggieMath/Complex.swift
@@ -61,6 +61,13 @@ public struct Complex: Hashable {
     }
 }
 
+#if compiler(>=5.5.2) && canImport(_Concurrency)
+
+@available(macOS 10.15, iOS 13, tvOS 13, watchOS 6, *)
+extension Complex: Sendable { }
+
+#endif
+
 extension Complex {
     
     @inlinable
diff --git a/Sources/DoggieMath/Polynomial.swift b/Sources/DoggieMath/Polynomial.swift
index 40ed6887..7d97b986 100644
--- a/Sources/DoggieMath/Polynomial.swift
+++ b/Sources/DoggieMath/Polynomial.swift
@@ -113,6 +113,13 @@ extension Polynomial: Codable {
     }
 }
 
+#if compiler(>=5.5.2) && canImport(_Concurrency)
+
+@available(macOS 10.15, iOS 13, tvOS 13, watchOS 6, *)
+extension Polynomial: Sendable { }
+
+#endif
+
 extension Polynomial: RandomAccessCollection, MutableCollection {
     
     public typealias Indices = Range<Int>
diff --git a/Sources/DoggieMath/Rational.swift b/Sources/DoggieMath/Rational.swift
index 13eeb009..fca6b480 100644
--- a/Sources/DoggieMath/Rational.swift
+++ b/Sources/DoggieMath/Rational.swift
@@ -125,6 +125,13 @@ extension Rational: CustomStringConvertible {
     }
 }
 
+#if compiler(>=5.5.2) && canImport(_Concurrency)
+
+@available(macOS 10.15, iOS 13, tvOS 13, watchOS 6, *)
+extension Rational: Sendable { }
+
+#endif
+
 extension Rational: SignedNumeric {
     
     @inlinable