ELI5 Why can our brains instantly recognise whether something is a right angle, even deviations of like 3°, but not instantly differentiate between 120° and 130°? What makes 90°, quarter of a circle, more recognisable than 120°, third of a circle?

ELI5 Why can our brains instantly recognise whether something is a right angle, even deviations of like 3°, but not instantly differentiate between 120° and 130°? What makes 90°, quarter of a circle, more recognisable than 120°, third of a circle?