Click either side of the cart to shove it — left of it shoves left, right of it shoves right. Arrow keys do the same. Jev keeps balancing throughout; a shove is an impulse it cannot predict, and it has to recover.
Decisions/sec and Jev's push trade off against each other: the cart gets whatever force you set,
held for one whole interval, so a strong push at a low rate overcorrects. Measured in
test/force-rate.mjs — at 10 decisions/sec no force balances
(42 at 10 N, 188 at 6 N, 68 at 4 N), while 4 N at 25/sec scores a clean 500.