PX

Syntax

PENREVERSE

PX

Explanation

PENREVERSE reverses the pen and bckground color when the turtle moves, drawing where there are no lines and erasing previously drawn lines.

The combination creates many possible effects. The exact appearance of the screen depands on the pen and background colors.

DRAW puts the pen down. See also PENDOWN, PENUP and PENERASE.

Example

? PX SETPC 15 FD \

? 30

?