(:):: "j:programs/progmenu"(: ): *: -- solar-system  I(<, )"Program Solar System by David Fanshier, Lakewood, CO. "Y"It llustrates motion of solar system. Moon revolves around earth 12 times "V"for every one revolution of the earth around the sun. The moon's orbit "V"(rm) is chosen to be only one-sixth as large as the earth's (re) -- so, "U"the moon's angular increment (1 divided by the radius) is six times as "X"large. USING STEP 1/re AND 1/rm, the moon would travel through its orbit "Y"six times as fast as the earth. We plot a new position for the moon twice "Y"for every position of the earth, so the moon travels twelve times as fast. "(<, )S:****************************************************************************:4@: d : put sun at center of screen+H :re is radius of earths orbit+ :rm is radius of moon's orbit :s is radius sun$ :e is radius of earth# :m is radius of moon% ,,, :background is black& ,,,> : yellow for sun* ,>,?^R, : green for earth, ,?:H,?:H,?:H : gray for moon* + : (,),+,: +: draw sun 5  : angular increment for moon is 1/rm8    @  : for earth is 1/re7 ( , ),,::PAINT (xe,ye),0 ' erase earth+ ( ): ( )6 ( , ),, ::PAINT (xe,ye),2' draw earth8 (,),, ::PAINT (xm,ym),0 ' erase earth\ ( ): ( ): (,),, ::PAINT (xm,ym),3' draw moon  7 (,),, :: PAINT (xm,ym),0' erase moon] ( ): ( ): (,),,:: PAINT (xm,ym),3 ' draw moon  %: ,: (,,<); ()2  initxsysrermsemLoopmoreoxeyexmymdonermCIRCLEqlarge.theMoonwouldtravelthroughitsorbitqzq1xzu1 llustratesmotionofsolarsystem.revolvesaroundearthtimesreduxrecoupstartgh