Click the flag to re-set the project. It shows two ways to draw a 5-point star against the xy-grid-30px backdrop. (A) Press SPACE to draw a star the easiest way by joining five points... but is it symmetrical on all five axes? (B) Press key Z to draw a star in a manner that's slightly more difficult to understand. Method two uses angles and a square root inside a loop of 5 iterations. The square root of 3²+9² = sqrt 9+81 = sqrt 90.
Draw STAR (A) on square paper using the first method. The pointer (a hidden apple sprite) will help to give the squared paper coordinates: Start at -3, -4 (which in pixels is -90,-120). Join to 0,5, to 3,-4, to -5, 2, to 5,2 to starting point -3,-4. Next draw Star (B) on the same squared paper. Notice that it does not fit exactly on top of Star (A). Why not? What is the mathematical basis for the angles 18º and (direction+144)º? Notice that the sprite is made to face UPwards (0º) at start! QUESTION: Which star has the better symmetry?
