begin adding float4 test ...
{528 501 996 818}
matrix multiply: together is:
[ 31  50]
[624 1004]
-------------------------------
[  1   0]
[ 22   3]

[  0   1]
[  2  10]

[ 14   1]
[  3   0]

[  2   3]
[ 13  21]
------------------------------
Two stage multiply gives:
[ 31  50]
[624 1004]