Visual hierarchy in 60 seconds: size, contrast and spacing decide what your users read first. Here is the 3-layer rule I use on every screen.

Stop syncing state with effects. Derive it during render instead — fewer bugs, fewer re-renders, cleaner components.

The rule of 72: divide 72 by your annual return to see how many years it takes to double your money. Simple math, life-changing habit.

Why does a prism split light? Each wavelength bends by a slightly different amount — that is dispersion, and it is why rainbows exist.