You can find it on the East Coast as well as the West Coast, and often the symbols are very well preserved, so each of these symbols has four bits -- it's a four-bit binary word -- you draw these lines in the sand randomly, and then you count off, and if it's an odd number, you put down one stroke, and if it's an even number, you put down two strokes.
东、西海岸都有。 这些符号通常都被良好的保存下来， 每个符号分为四部分，可看做四个二进制位组成的单元--- 你在沙地里随意画下这样的线段，然后数一下， 如果有奇数条线段，划下一条线， 而如果有偶数条，划两条线。