Spinning or not?

Here is an interesting "illusion". This is a conversion of a program created by Charlie Veniot using his Basic Anywhere Machine.

The program will show you an image that looks like it is spinning and then it will show you how it is done.

Enjoy.



xmax = 600
ymax = 600
title$ = "Spinning? Yes or No?"
center_x = windowpos_centered
center_y = windowpos_centered
WindowOpen(1,title$,center_x,center_y,xmax,ymax,WindowMode(1,0,0,0,0),1)
SetWindowAutoClose(1, 0)
CanvasOpen(1,xmax,ymax,0,0,xmax,ymax,0)

' Charlie Veniot's BASIC Anywhere Machine mod of the program by B+
' https://basicanywheremachine.neocities.org/sample_programs/BAM_SamplePrograms?page=spinning_dots_illusion

pi = 3.141592654

roundAroundLmt = 3
x0 = xmax / 2
y0 = ymax / 2
a24 = pi * (2 / 24)
r = 240

loopcnt = 0
tinyCircleCnt = 0

do
   if loopcnt < roundAroundLmt then
tinyCircleCnt = 11
end if
   if loopcnt = roundAroundLmt then
tinyCircleCnt = 0
end if
   if loopcnt > roundAroundLmt then
       if tinyCircleCnt < 11 then
tinyCircleCnt = tinyCircleCnt + 1
end if
   end if
   for a = 0 to pi * 2 step pi / 180
setColor(rgb(82, 82, 82))
       CircleFill(x0, y0, 251)
       for i = 0 to tinyCircleCnt
           if loopcnt > roundAroundLmt - 1 then
               a24i = a24 * i
               xs = x0 + (r * cos(a24i))
               ys = y0 + (r * sin(a24i))
               xe = x0 + (r * cos(a24i + pi))
               ye = y0 + (r * sin(a24i + pi))
               setColor(rgb(192, 192, 192))
               line(xs, ys, xe, ye)
           end if
           cv1 = cos(a + (pi * (i/12)))
           x = x0 + (cv1 * r * cos(a24 * i))
           y = y0 + (cv1 * r * sin(a24 * i))
           setColor(rgb(255, 255, 255))
           CircleFill(x, y, 10)
       next
       'wait(4)
       if key(27) = 1 then
exit do
end if
       update()
   next
   loopcnt = (loopcnt mod 15) + 1
if Not WindowExists(1) Or WindowEvent_Close(1) Then
end
end if
update()
loop until key(27) = 1


J