PROGRAM wheel CALL initial(r,omega,vcm,t,dt,xmax) DO while x <= xmax LET x = -r*cos(omega*t) + vcm*t LET y = r*sin(omega*t) ! note the semicolon after PLOT x,y PLOT x,y; ! abbreviation of PLOT POINT: LET t = t + dt LOOP END SUB initial(r,omega,vcm,t,dt,xmax) LET t = 0 LET r = 1 ! radius of wheel LET omega = 1 ! angular frequency of wheel LET vcm = r*omega ! velocity of center of mass LET dt = 0.01 ! time increment LET xmin = -1 LET xmax = 50 LET mx = 0.01*(xmax - xmin) SET WINDOW xmin-mx,xmax+mx,-4,4 ! draw ground at y = -r (bottom of wheel) PLOT LINES: xmin,-r;xmax,-r END SUB