BUG Number #7

Created Apr 4, 2026; Last updated Apr 4, 2026

What happened?

This BUG is the result of me trying to plot an integral curve/trajectory for the ODE system x' = -y; y' = x. Normally, the integral curves of this system would form circles in the x-y plane (fun fact: you can get spirals by subtracting, e.g., 0.5y from y'). However, in this case the resolution of the “measurements” is very coarse. When connecting the measurement points, we get differently rotated pentagons instead of a smooth circle, resulting in this pretty neat looking “portal”. The intersections of these lines even form an “inner circle”. If we were to sample enough points, we would however get the “outer circle” as the correct result. There is Python code available for you to play with.