Generates fractal patterns seen on conus "textile" sea shells. This pattern consists of lines whereas my ealier crab patterns consisted only of fractal triangles. These correspond to two different shell patterns. Click "R" to see real shell pattern, "A" to see another. Click crab or spacebar to make crab disappear. Every time you click flag, the patterns is different because the randomly generated first row determines subsequent patterning, with some further random deviation you can set. First we make a row with a few red spots randomly distributed (hidden) representing pigment generating chemicals. Then, white spaces next to only one red will be red in the next row (all other spaces are white). Each new row follows this simple change rule. In this code I use two different tiles, one slanting left and one slanting right.
Crab outline by Kathy. Pattern: generated by my code, with tiles that are slanted lines. The pattern slightly different each time. Code creates a row of dots (stamps a tiny triangle, but but a round pen dot works almost as well). A few are red (orangish red), the rest white. Code uses lists to keep track of dots. Then sprite moves down a row and follows the simple rule of change: white clones next to only one red turn red, all other clones will be white. So, the space with a red clone will always be white in the next row, as will white clones next to two reds. Each row is permanent, but the next row is a variant of the previous, as on mollusc conus "textile" sea shells. The rules for generating are similar to a process in growing shells where the spread of pigment is like a spreading infection, with a period immunity--the analogy is that a space previously red becomes "immune" to becoming colored in the next row. Shells grow in this manner leaving a permanent record of pattern in the previous rows. I added an embellishment that isn't directly part of the above mechanism: a striped region that replaces a yellow pigment where a white triangle would be otherwise. Some shells have this, and probably has to do with a travelling chemical promoting a certain pigment.
