uniform half4 colorGreen, colorRed;
uniform float2x2 testMatrix2x2;  // equals (1, 2, 3, 4)

half4 main(float2 coords) {
    float4 f4 = float4(testMatrix2x2);

    // These matrices are intentionally assembled off-kilter; the vectors shouldn't line up with the
    // natural matrix stride. Metal and SPIR-V will need to reorder the data to make it fit.
    bool ok =  float2x3(f4.xyzw, f4.xy)                 == float2x3(1, 2, 3, 4, 1, 2);
    ok = ok && float2x4(f4.xyz, f4.wxyz, f4.w)          == float2x4(1, 2, 3, 4, 1, 2, 3, 4);
    ok = ok && float3x3(f4.xy, f4.zw, f4.xyzw, f4.x)    == float3x3(1, 2, 3, 4, 1, 2, 3, 4, 1);
    ok = ok && float4x2(f4.xyz, f4.wxyz, f4.w)          == float4x2(1, 2, 3, 4, 1, 2, 3, 4);
    ok = ok && float4x3(f4.x, f4.yzwx, f4.yzwx, f4.yzw) == float4x3(1, 2, 3,
                                                                    4, 1, 2,
                                                                    3, 4, 1,
                                                                    2, 3, 4);
    return ok ? colorGreen : colorRed;
}