Alt text:
'At the stroke of midnight, your brother will be hurtling sideways at an altitude of 150 meters' is a regular physics prediction about your nonmagical trebuchet, whereas 'you are cursed to build a brother-launching trebuchet' falls out of the Lagrangian.
"I'll take 'I am not good at math so ELI5 the joke to me' for $100, Alex."
read OP's comment in here that says : "explainXKCD.com"...
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