2. Copy and paste the following three processes into the editing window.
TO xq:c:r； celestial body
setpc :c
pd (stampoval :r :r "true)
end
To yd: j; Yuedi
pd xq 9 20
rt :j pu fd 50 rt 90 pd
Xq 8 10 Wait 15 xq 15 10
lt 90 bk 50 lt :j xq 15 20
pu rt 2.5 fd 200*0.0872 rt 2.5
yd :j+ 15
end
To ryx, sun, moon and stars
Draw pd xq 12 50
pu fd 200 rt 90
yd 0
end
3. Press F2 again to define the process and return to the command window.
4. Enter cs ryx and press Enter to run the simulation animation of the sun, the earth and the moon.
After inspection, there is nothing wrong with the program. I guess you can't operate it. Just follow the steps mentioned above. In order to see the effect better, please arrange the command window and the graphics window left and right (just click the tile command under the windows menu in the LOGO).