Use TURBO mode to see the demonstration pattern. (Press the <Shift> key and click the Green Flag for TURBO mode). The "1 Line Challenge" is to produce an interesting pattern on the screen using only one line of code to calculate the color of each pixel. You may only change the "set pen color to ..." line in this project. Please put your remixed "1 Line Challenge" Projects in the Studio https://scratch.mit.edu/studios/2825709/ If you just had to break the rules please put your "Not Quite A 1 Line Project" projects in this studio instead https://scratch.mit.edu/studios/2825759/ "See Inside" for more Rules, Rewards, a Short Tutorial etc.
The basis of this pattern is a 'color wheel' function: atan(y/x)/0.9. Adding a simple radial function to that (i.e. an expression where x and y only occur combined as x*x+y*y) results in a nice spiral. Then I added two more radial functions; an exponential function that causes the outer rim to be condensed to circles (ending in colorful noise with tiny moiré patterns), and a sine-based function that normally gives a ripple effect (like throwing a stone in the pond), but in this case give a nice 'smudge' effect.
