Main sections
CLEARSCREEN
CLEARSCREEN [color%]
Deletes the back buffer with the colour: "color%" and uses that colour for presenting an empty back buffer after a SHOWSCREEN. If you set colour% to -1, from now on neither the back buffer, nor the Z buffer are cleared in a SHOWSCREEN call. The content of the back buffer is undefined in that case!
CLEARSCREEN RGB(255,0,0)
WHILE TRUE
PRINT "TEST", 100,100
SHOWSCREEN
WEND