diff --git a/src/GameCult.Caching.MessagePack/CultMathJson.cs b/src/GameCult.Caching.MessagePack/CultMathJson.cs
index 0e65bf22..29c312da 100644
--- a/src/GameCult.Caching.MessagePack/CultMathJson.cs
+++ b/src/GameCult.Caching.MessagePack/CultMathJson.cs
@@ -14,7 +14,7 @@ namespace GameCult.Caching.MessagePack;
 /// The canonical System.Text.Json shape of every public CultMath value type, the JSON twin of
 /// <see cref="CultMathResolver"/>. Vectors, quaternions and colors are objects keyed by their
 /// field names (<c>{"x":1,"y":2}</c>), matrices are arrays of row objects, <c>rect</c> is
-/// <c>{"min":..,"max":..}</c>, <c>CultCellular</c> is <c>{"nearest":..,"edge":..,"id":..}</c>, and <c>CultPhasor</c> is <c>{"cos":..,"sin":..}</c>.
+/// <c>{"min":..,"max":..}</c>, <c>CultCellular</c> is <c>{"nearest":..,"edge":..,"id":..}</c>, <c>CultPhasor</c> is <c>{"cos":..,"sin":..}</c>, and <c>SpanNoise</c> is <c>{"field":..,"curvature":..,"fold":..}</c>.
 /// Property names are fixed: <c>PropertyNamingPolicy</c> does not rename them, and
 /// <c>PropertyNameCaseInsensitive</c> makes reading case-insensitive.
 /// <para>
@@ -481,7 +481,7 @@ public static class CultMathJson
             Add<Random, uint>(UIntScalar.Instance, new Fields<uint>(("state", Val<uint>())),
                 a => new Random { state = a[0] }, (v, a) => a[0] = v.state),
 
-            // Compositions: matrices are arrays of row objects, rect is {min, max}, CultCellular is {nearest, edge, id}, CultPhasor is {cos, sin}.
+            // Compositions: matrices are arrays of row objects, rect is {min, max}, CultCellular is {nearest, edge, id}, CultPhasor is {cos, sin}, SpanNoise is {field, curvature, fold}.
             Add<float2x2, float>(f, new Rows<float>(2, Xy<float>()),
                 a => new float2x2(a[0], a[1], a[2], a[3]),
                 (v, a) => { a[0] = v[0].x; a[1] = v[0].y; a[2] = v[1].x; a[3] = v[1].y; }),
@@ -514,6 +514,13 @@ public static class CultMathJson
                     a[0] = v.cos.x; a[1] = v.cos.y; a[2] = v.cos.z; a[3] = v.cos.w;
                     a[4] = v.sin.x; a[5] = v.sin.y; a[6] = v.sin.z; a[7] = v.sin.w;
                 }),
+            Add<SpanNoise, float>(f, new Fields<float>(("field", Xyzw<float>()), ("curvature", Val<float>()), ("fold", Val<float>())),
+                a => new SpanNoise(new float4(a[0], a[1], a[2], a[3]), a[4], a[5]),
+                (v, a) =>
+                {
+                    a[0] = v.field.x; a[1] = v.field.y; a[2] = v.field.z; a[3] = v.field.w;
+                    a[4] = v.curvature; a[5] = v.fold;
+                }),
         };
 
         var map = new Dictionary<Type, JsonConverter>();
diff --git a/src/GameCult.Caching.MessagePack/CultMathResolver.cs b/src/GameCult.Caching.MessagePack/CultMathResolver.cs
index 8383a464..529ed2e7 100644
--- a/src/GameCult.Caching.MessagePack/CultMathResolver.cs
+++ b/src/GameCult.Caching.MessagePack/CultMathResolver.cs
@@ -180,7 +180,7 @@ public sealed class CultMathResolver : IFormatterResolver
                     return value;
                 }),
 
-            // Compositions: matrices are rows, rect is [min, max], CultCellular is [nearest, edge, id], CultPhasor is [cos, sin].
+            // Compositions: matrices are rows, rect is [min, max], CultCellular is [nearest, edge, id], CultPhasor is [cos, sin], SpanNoise is [field, curvature, fold].
             Shape<float2x2>((ref MessagePackWriter w, float2x2 v) => { w.WriteArrayHeader(2); PutFloat2(ref w, v[0]); PutFloat2(ref w, v[1]); },
                 (ref MessagePackReader r) =>
                 {
@@ -236,6 +236,22 @@ public sealed class CultMathResolver : IFormatterResolver
                     }
                     return value;
                 }),
+            Shape<SpanNoise>((ref MessagePackWriter w, SpanNoise v) => { w.WriteArrayHeader(3); PutFloat4(ref w, v.field); w.Write(v.curvature); w.Write(v.fold); },
+                (ref MessagePackReader r) =>
+                {
+                    var value = default(SpanNoise);
+                    for (int i = 0, n = r.ReadArrayHeader(); i < n; i++)
+                    {
+                        switch (i)
+                        {
+                            case 0: value.field = GetFloat4(ref r); break;
+                            case 1: value.curvature = r.ReadSingle(); break;
+                            case 2: value.fold = r.ReadSingle(); break;
+                            default: r.Skip(); break;
+                        }
+                    }
+                    return value;
+                }),
         };
 
         var map = new Dictionary<Type, object>();
diff --git a/tests/GameCult.Caching.Tests/CultMathJsonTests.cs b/tests/GameCult.Caching.Tests/CultMathJsonTests.cs
index 90d739be..26474907 100644
--- a/tests/GameCult.Caching.Tests/CultMathJsonTests.cs
+++ b/tests/GameCult.Caching.Tests/CultMathJsonTests.cs
@@ -45,6 +45,8 @@ namespace GameCult.Caching.Tests
                 """{"nearest":{"x":1,"y":2,"z":3,"w":4},"edge":{"x":5,"y":6,"z":7,"w":8},"id":0.25}""");
             Json(new CultPhasor(new float4(1f, 2f, 3f, 4f), new float4(5f, 6f, 7f, 8f))).Should().Be(
                 """{"cos":{"x":1,"y":2,"z":3,"w":4},"sin":{"x":5,"y":6,"z":7,"w":8}}""");
+            Json(new SpanNoise(new float4(1f, 2f, 3f, 4f), 0.25f, 0.5f)).Should().Be(
+                """{"field":{"x":1,"y":2,"z":3,"w":4},"curvature":0.25,"fold":0.5}""");
         }
 
         [Test]
@@ -69,6 +71,7 @@ namespace GameCult.Caching.Tests
             RoundTrip(new rect(-1f, -2f, 5f, 7f));
             RoundTrip(new CultCellular(new float4(1, 2, 3, 4), new float4(5, 6, 7, 8), 0.25f));
             RoundTrip(new CultPhasor(new float4(1, 2, 3, 4), new float4(5, 6, 7, 8)));
+            RoundTrip(new SpanNoise(new float4(1, 2, 3, 4), 0.25f, 0.5f));
         }
 
         [Test]
diff --git a/tests/GameCult.Caching.Tests/CultMathSerializationTests.cs b/tests/GameCult.Caching.Tests/CultMathSerializationTests.cs
index 98f126af..7836663f 100644
--- a/tests/GameCult.Caching.Tests/CultMathSerializationTests.cs
+++ b/tests/GameCult.Caching.Tests/CultMathSerializationTests.cs
@@ -102,6 +102,7 @@ namespace GameCult.Caching.Tests
             RoundTrip(new rect(-1f, -2f, 5f, 7f));
             RoundTrip(new CultCellular(new float4(1, 2, 3, 4), new float4(5, 6, 7, 8), 0.25f));
             RoundTrip(new CultPhasor(new float4(1, 2, 3, 4), new float4(5, 6, 7, 8)));
+            RoundTrip(new SpanNoise(new float4(1, 2, 3, 4), 0.25f, 0.5f));
         }
 
         [Test]
@@ -137,6 +138,11 @@ namespace GameCult.Caching.Tests
                 "92" +
                 "94CA3F800000CA40000000CA40400000CA40800000" +
                 "94CA40A00000CA40C00000CA40E00000CA41000000");
+            Hex(new SpanNoise(new float4(1f, 2f, 3f, 4f), 0.25f, 0.5f)).Should().Be(
+                "93" +
+                "94CA3F800000CA40000000CA40400000CA40800000" +
+                "CA3E800000" +
+                "CA3F000000");
         }
 
         [Test]