str$="Hello, World! "
direction=0	#value of 0: to the right, 1: to the left.
tlx=10		#Top left x
tly=10		#Top left y
fastgraphics
font "Arial",20,100	#The Font configuration (Font face, size, weight)

main:
while clickb=0
	if direction=0 then
		str$=RIGHT(str$,1) + LEFT(str$,length(str$)-1)
	else
		str$=MID(str$,2,length(str$)-1)+LEFT(str$,1)
	end if
	refresh
	clg
	color red
	text tlx,tly,str$
	pause .1
end while
	#Note: textheight() and textwidth() depends on the latest configuration of the FONT command.
if clickb=1 and clickx>=tlx and clickx<=tlx+textwidth(str$) and clicky>=tly and clicky<=tly+textheight() then
	direction=NOT direction
end if
clickclear
goto main