Parameters in brackets aren't necessary. GLINE X1,Y1,X2,Y2,[COLOR] ...This one is pretty self-explanatory. You draw a line from point (X1,Y1) to (X2,Y2). GCIRCLE CX,CY,R,[COLOR] ...For this one you specify the center coordinates of the center (CX,CY) and the radius R of the circle. GCLS [COLOR] ...This one "clears" the graphics screen by filling the entire screen with a single color.