Sets the pen's position, mode, and hardware-dependent characteristics according to the information in the
The characteristics input is a list with the following members: [PENDOWNP PENMODE PENSIZE PENCOLOR PENPAINT].
The format of this list may change in futures version of FMSLogo, as additional pen characteristics are added.
To guarantee portability, the input should be taken from an earlier invocation of PEN.
CLEARSCREEN REPEAT 4 [FORWARD 100 RIGHT 90] MAKE "savepen PEN CLEARSCREEN SETPENSIZE [20 20] REPEAT 4 [FORWARD 100 RIGHT 90] SETPEN :savepen CLEARSCREEN REPEAT 4 [FORWARD 100 RIGHT 90]