🎮 Parallel or Perpendicular?

📖 About this game

A game on parallel and perpendicular lines, with its two rules: parallel lines have the same slope, and the slopes of perpendicular lines have a product of negative one. Why three baskets rather than a two-way question: most pairs of lines in the plane are neither parallel nor perpendicular, and without the third basket the learner would simply learn that one of two answers must be true. Both equations are given in slope-intercept form so the slope is read out of the equation itself, which is the lesson, rather than memorising two described pairs. The verdict is computed from the two slopes and never typed by hand: equal slopes are parallel, a product of negative one is perpendicular, and anything else is neither, so the name on the basket can never contradict the equations shown. Every case is generated from one slope: itself for parallel, its negative reciprocal for perpendicular, and then the two expected mistakes of the lesson, flipping the sign alone and inverting the fraction alone, both of which land in the third basket and are therefore measured. The two slopes and their product appear at the reveal as proof. Nine rounds. No sign-up.

🕹️ How to play

1. Read the slope out of each equation: it is the coefficient of x.
2. Equal slopes mean the lines are parallel.
3. A product of negative one means perpendicular; anything else is neither.
4. Every pair you get first try counts for you.