diff --git a/Sources/OpenGestures/Util/AdditiveArithmetic.swift b/Sources/OpenGestures/Util/AdditiveArithmetic.swift
new file mode 100644
index 0000000..96bd33e
--- /dev/null
+++ b/Sources/OpenGestures/Util/AdditiveArithmetic.swift
@@ -0,0 +1,69 @@
+//
+//  AdditiveArithmetic.swift
+//  OpenGestures
+//
+//  Audited for 9126.1.5
+//  Status: Complete
+
+public import OpenCoreGraphicsShims
+
+// MARK: - _AdditiveArithmetic
+
+package protocol _AdditiveArithmetic: Equatable {
+    static var zero: Self { get }
+
+    static func + (lhs: Self, rhs: Self) -> Self
+    static func += (lhs: inout Self, rhs: Self)
+    static func - (lhs: Self, rhs: Self) -> Self
+    static func -= (lhs: inout Self, rhs: Self)
+}
+
+extension _AdditiveArithmetic {
+    package static func += (lhs: inout Self, rhs: Self) {
+        lhs = lhs + rhs
+    }
+
+    package static func -= (lhs: inout Self, rhs: Self) {
+        lhs = lhs - rhs
+    }
+}
+
+// MARK: - Double + _AdditiveArithmetic
+
+extension Double: _AdditiveArithmetic {}
+
+// MARK: - CGPoint + _AdditiveArithmetic
+
+extension CGPoint: _AdditiveArithmetic {
+    package static func + (lhs: CGPoint, rhs: CGPoint) -> CGPoint {
+        CGPoint(x: lhs.x + rhs.x, y: lhs.y + rhs.y)
+    }
+
+    package static func - (lhs: CGPoint, rhs: CGPoint) -> CGPoint {
+        CGPoint(x: lhs.x - rhs.x, y: lhs.y - rhs.y)
+    }
+}
+
+// MARK: - CGVector + _AdditiveArithmetic
+
+extension CGVector: _AdditiveArithmetic {
+    package static func + (lhs: CGVector, rhs: CGVector) -> CGVector {
+        CGVector(dx: lhs.dx + rhs.dx, dy: lhs.dy + rhs.dy)
+    }
+
+    package static func - (lhs: CGVector, rhs: CGVector) -> CGVector {
+        CGVector(dx: lhs.dx - rhs.dx, dy: lhs.dy - rhs.dy)
+    }
+}
+
+// MARK: - CGSize + _AdditiveArithmetic
+
+extension CGSize: _AdditiveArithmetic {
+    package static func + (lhs: CGSize, rhs: CGSize) -> CGSize {
+        CGSize(width: lhs.width + rhs.width, height: lhs.height + rhs.height)
+    }
+
+    package static func - (lhs: CGSize, rhs: CGSize) -> CGSize {
+        CGSize(width: lhs.width - rhs.width, height: lhs.height - rhs.height)
+    }
+}
diff --git a/Sources/OpenGestures/Util/LocationContaining.swift b/Sources/OpenGestures/Util/LocationContaining.swift
index 6cf3eb3..0c6588c 100644
--- a/Sources/OpenGestures/Util/LocationContaining.swift
+++ b/Sources/OpenGestures/Util/LocationContaining.swift
@@ -27,9 +27,26 @@ extension Never: LocationContaining {
     public var location: CGPoint { fatalError() }
 }
 
-// MARK: - IdentifiableLocation [WIP]
+// MARK: - IdentifiableLocation
 
-package struct IdentifiableLocation<ID> where ID: Hashable {
+package struct IdentifiableLocation<ID>: Identifiable where ID: Hashable {
     package var id: ID
     package var location: CGPoint
 }
+
+extension IdentifiableLocation: LocationContaining {}
+
+extension IdentifiableLocation: NestedCustomStringConvertible {}
+
+extension IdentifiableLocation: VectorContaining {
+    package typealias VectorType = CGPoint
+
+    package var vector: CGPoint {
+        get { location }
+        set { location = newValue }
+    }
+}
+
+extension IdentifiableLocation: ThresholdAdjustable {
+    package typealias Threshold = Double
+}
diff --git a/Sources/OpenGestures/Util/ThresholdAdjustable.swift b/Sources/OpenGestures/Util/ThresholdAdjustable.swift
new file mode 100644
index 0000000..c4a83cd
--- /dev/null
+++ b/Sources/OpenGestures/Util/ThresholdAdjustable.swift
@@ -0,0 +1,52 @@
+//
+//  ThresholdAdjustable.swift
+//  OpenGestures
+//
+//  Audited for 9126.1.5
+//  Status: Complete
+
+public import OpenCoreGraphicsShims
+
+// MARK: - ThresholdAdjustable
+
+/// A value whose backing vector can consume a threshold-sized movement.
+package protocol ThresholdAdjustable: VectorContaining {
+    /// The scalar threshold type used to gate movement.
+    associatedtype Threshold
+
+    /// Consumes up to `threshold` units from `movement`.
+    ///
+    /// When `movement` reaches the threshold, this subtracts the threshold-sized
+    /// portion of `movement` from `vector` and returns that consumed movement.
+    /// Returns `nil` without mutation when `threshold` is not positive or
+    /// `movement` is below threshold.
+    mutating func consume(_ threshold: Threshold, from movement: VectorType) -> VectorType?
+}
+
+extension ThresholdAdjustable where Threshold == Double {
+    package mutating func consume(_ threshold: Double, from movement: VectorType) -> VectorType? {
+        guard threshold > 0 else { return nil }
+
+        let movementMagnitude = movement.magnitude
+        guard movementMagnitude >= threshold else { return nil }
+
+        let scale = threshold / movementMagnitude
+        let consumedMovement = movement.scaled(by: scale)
+        vector -= consumedMovement
+        return consumedMovement
+    }
+}
+
+// MARK: - ThresholdAdjustable Conformance
+
+extension Double: ThresholdAdjustable {
+    package typealias Threshold = Double
+}
+
+extension CGPoint: ThresholdAdjustable {
+    package typealias Threshold = Double
+}
+
+extension CGVector: ThresholdAdjustable {
+    package typealias Threshold = Double
+}
diff --git a/Sources/OpenGestures/Util/VectorArithmetic.swift b/Sources/OpenGestures/Util/VectorArithmetic.swift
new file mode 100644
index 0000000..4873d97
--- /dev/null
+++ b/Sources/OpenGestures/Util/VectorArithmetic.swift
@@ -0,0 +1,85 @@
+//
+//  VectorArithmetic.swift
+//  OpenGestures
+//
+//  Audited for 9126.1.5
+//  Status: Complete
+
+public import OpenCoreGraphicsShims
+
+// MARK: - VectorArithmetic
+
+package protocol VectorArithmetic: _AdditiveArithmetic {
+    var magnitude: Double { get }
+
+    func scaled(by rhs: Double) -> Self
+}
+
+// MARK: - VectorArithmetic Conformance
+
+extension Double: VectorArithmetic {
+    package var magnitude: Double {
+        abs(self)
+    }
+
+    package func scaled(by rhs: Double) -> Double {
+        self * rhs
+    }
+}
+
+extension CGPoint: VectorArithmetic {
+    package var magnitude: Double {
+        hypot(abs(x), abs(y))
+    }
+
+    package func scaled(by rhs: Double) -> CGPoint {
+        CGPoint(x: x * rhs, y: y * rhs)
+    }
+}
+
+extension CGVector: VectorArithmetic {
+    package var magnitude: Double {
+        hypot(abs(dx), abs(dy))
+    }
+
+    package func scaled(by rhs: Double) -> CGVector {
+        CGVector(dx: dx * rhs, dy: dy * rhs)
+    }
+}
+
+// MARK: - VectorContaining
+
+package protocol VectorContaining {
+    associatedtype VectorType: VectorArithmetic
+
+    var vector: VectorType { get set }
+}
+
+// MARK: - VectorContaining Conformance
+
+extension Double: VectorContaining {
+    package typealias VectorType = Double
+
+    package var vector: Double {
+        get { self }
+        set { self = newValue }
+    }
+}
+
+extension CGPoint: VectorContaining {
+    package typealias VectorType = CGPoint
+
+    package var vector: CGPoint {
+        get { self }
+        set { self = newValue }
+    }
+}
+
+extension CGVector: VectorContaining {
+    package typealias VectorType = CGVector
+
+    package var vector: CGVector {
+        get { self }
+        set { self = newValue }
+    }
+}
diff --git a/Tests/OpenGesturesTests/Util/AdditiveArithmeticTests.swift b/Tests/OpenGesturesTests/Util/AdditiveArithmeticTests.swift
new file mode 100644
index 0000000..d6f3626
--- /dev/null
+++ b/Tests/OpenGesturesTests/Util/AdditiveArithmeticTests.swift
@@ -0,0 +1,63 @@
+//
+//  AdditiveArithmeticTests.swift
+//  OpenGesturesTests
+
+import OpenCoreGraphicsShims
+import OpenGestures
+import Testing
+
+@Suite
+struct AdditiveArithmeticTests {
+    @Test
+    func doubleOperations() {
+        #expect(Double.zero == 0.0)
+        #expect(3.0 + 2.0 == 5.0)
+        #expect(3.0 - 2.0 == 1.0)
+
+        var value = 4.0
+        value += 1.5
+        #expect(value == 5.5)
+        value -= 2.5
+        #expect(value == 3.0)
+    }
+
+    @Test
+    func pointOperations() {
+        #expect(CGPoint.zero == CGPoint(x: 0, y: 0))
+        #expect(
+            CGPoint(x: 3, y: 4) + CGPoint(x: 1, y: 2)
+                == CGPoint(x: 4, y: 6)
+        )
+        #expect(
+            CGPoint(x: 3, y: 4) - CGPoint(x: 1, y: 2)
+                == CGPoint(x: 2, y: 2)
+        )
+
+        var point = CGPoint(x: 2, y: 3)
+        point += CGPoint(x: 4, y: 5)
+        #expect(point == CGPoint(x: 6, y: 8))
+        point -= CGPoint(x: 1, y: 1)
+        #expect(point == CGPoint(x: 5, y: 7))
+    }
+
+    @Test
+    func vectorAndSizeOperations() {
+        #expect(
+            CGVector(dx: 5, dy: 7) + CGVector(dx: 1, dy: 2)
+                == CGVector(dx: 6, dy: 9)
+        )
+        #expect(
+            CGVector(dx: 5, dy: 7) - CGVector(dx: 1, dy: 2)
+                == CGVector(dx: 4, dy: 5)
+        )
+
+        #expect(
+            CGSize(width: 8, height: 6) + CGSize(width: 2, height: 1)
+                == CGSize(width: 10, height: 7)
+        )
+        #expect(
+            CGSize(width: 8, height: 6) - CGSize(width: 2, height: 1)
+                == CGSize(width: 6, height: 5)
+        )
+    }
+}
diff --git a/Tests/OpenGesturesTests/Util/RingBufferTests.swift b/Tests/OpenGesturesTests/Util/RingBufferTests.swift
index 669de40..d41f5e1 100644
--- a/Tests/OpenGesturesTests/Util/RingBufferTests.swift
+++ b/Tests/OpenGesturesTests/Util/RingBufferTests.swift
@@ -2,7 +2,7 @@
 //  RingBufferTests.swift
 //  OpenGesturesTests
 
-@_spi(Private) import OpenGestures
+import OpenGestures
 import Testing
 
 // MARK: - RingBufferTests
diff --git a/Tests/OpenGesturesTests/Util/ThresholdAdjustableTests.swift b/Tests/OpenGesturesTests/Util/ThresholdAdjustableTests.swift
new file mode 100644
index 0000000..2515e55
--- /dev/null
+++ b/Tests/OpenGesturesTests/Util/ThresholdAdjustableTests.swift
@@ -0,0 +1,19 @@
+//
+//  ThresholdAdjustableTests.swift
+//  OpenGesturesTests
+
+import OpenGestures
+import Testing
+
+@Suite
+struct ThresholdAdjustableTests {
+    @Test
+    func consumeThresholdForDouble() {
+        var value = 10.0
+
+        let consumed = value.consume(3.0, from: 8.0)
+
+        #expect(consumed == 3.0)
+        #expect(value == 7.0)
+    }
+}
diff --git a/Tests/OpenGesturesTests/Util/VectorArithmeticTests.swift b/Tests/OpenGesturesTests/Util/VectorArithmeticTests.swift
new file mode 100644
index 0000000..ebdb716
--- /dev/null
+++ b/Tests/OpenGesturesTests/Util/VectorArithmeticTests.swift
@@ -0,0 +1,31 @@
+//
+//  VectorArithmeticTests.swift
+//  OpenGesturesTests
+
+import OpenCoreGraphicsShims
+import OpenGestures
+import Testing
+
+@Suite
+struct VectorArithmeticTests {
+    @Test
+    func doubleMagnitudeAndScaling() {
+        #expect(12.0.magnitude == 12.0)
+        #expect((-12.0).magnitude == 12.0)
+        #expect(12.0.scaled(by: 0.25) == 3.0)
+    }
+
+    @Test
+    func pointMagnitudeAndScaling() {
+        let point = CGPoint(x: 3, y: 4)
+        #expect(point.magnitude == 5.0)
+        #expect(point.scaled(by: 2) == CGPoint(x: 6, y: 8))
+    }
+
+    @Test
+    func vectorMagnitudeAndScaling() {
+        let vector = CGVector(dx: 5, dy: 12)
+        #expect(vector.magnitude == 13.0)
+        #expect(vector.scaled(by: 0.5) == CGVector(dx: 2.5, dy: 6.0))
+    }
+}