code: function transpose(out, a) {
    // If we are transposing ourselves we can skip a few steps but have to cache some values
    if (out === a) {
      var a01 = a[1],
          a02 = a[2],
          a12 = a[5];
      out[1] = a[3];
      out[2] = a[6];
      out[3] = a01;
      out[5] = a[7];
      out[6] = a02;
      out[7] = a12;
    } else {
      out[0] = a[0];
      out[1] = a[3];
      out[2] = a[6];
      out[3] = a[1];
      out[4] = a[4];
      out[5] = a[7];
      out[6] = a[2];
      out[7] = a[5];
      out[8] = a[8];
    }
  
    return out;
  }
docs: Transpose the values of a mat3
  
  @param {mat3} out the receiving matrix
  @param {mat3} a the source matrix
  @returns {mat3} out