I had the Datel Genius mouse for my spectrum. It came bundled with the OCP Art Studio (which never worked on my spectrum). You could 'peek' into memory addresse

I had the Datel Genius mouse for my spectrum. It came bundled with the OCP Art Studio (which never worked on my spectrum). You could 'peek' into memory addresses to find the position and button state, so I wrote silly little BASIC programs for it.