In 1969 when I was selling prints in the Merrion Centre art exhibition in Leeds, some one said “Are your drawings done by computer”. At the time computers were rubbish, so I built my own machine . 8 clear perspex rulers one way and 8 rulers crossing them enclosed within a box I built. The rulers had alternate inches marked or not marked with a line. Any ruler could be pushed in or out to change the whole pattern of continuous lines. I applied my colours to the lines on this one.