function copy$7(out, a) {
    out[0] = a[0];
    out[1] = a[1];
    out[2] = a[2];
    out[3] = a[3];
    out[4] = a[4];
    out[5] = a[5];
    return out;
  }
Copy the values from one mat2d to another

@param {mat2d} out the receiving matrix
@param {ReadonlyMat2d} a the source matrix
@returns {mat2d} out