Every word is a ray. It starts at the gold centre, the root, and puts one letter on each ring: its first letter on ring 1, its second on ring 2. Words run A to Z from left to right. Words that begin alike share a ray, and it forks where their letters part, so CAR, CARD, CART and CARTOON are one ray. A gold ring round a letter marks where a word ends: CAR is a word, and so is CART, one ring further out.

Every node keeps a slot for each of the 26 letters, so following a word is one step per letter, with nothing to search. That is why a lookup depends on the word's length and not on how many words there are: Three sizes shows 20, 200 and 2,000 words, all seven rings wide. Memory turns the sunburst to show those slots, and how few of them hold anything.

Type and the sunburst opens around your letters: the gold wedge is every word they could become, read out at the rim. Spell check finds the words one edit away, cutting every branch the moment it goes two edits wrong.