Spirolaterals with the turtle
Alain Busser
Teacher (math and CS) at Lycée Roland-Garros, Le Tampon
Abstract
Professor Frank C Odds, a world leading authority in medical mycology, devised in the 1960s, while he was a student, the beautiful geometric patterns known as spirolaterals:
For a spirolateral, two parameters are required:
- an angle (the rotation of the turtle at each step)
- an number of iterations (or the length of a list of distances at which the turtle travels)
A scientific experiment requires that one repeats the trials while modifying the values of the parameters. This is best achieved with html inputs of type range. As JSXGraph is programmed in JavaScript, I found it easy to make these inputs communicate with the turtle. This allowed to
- publish an interactive presentation of Odds’s spirolaterals
- add a variant that Odds devised in the mean time
- add another variant, still invented by Odds
- and seeing this, gave to Odds a new idea
Franck C Odds recently passed out, so this presentation will be a tribute to him.