Count
Why you can count four things at a glance, but not forty
Up to about four objects, your eyes simply know how many there are. Past that you estimate: how estimates go wrong, and how to make them better.
Blog
Short pieces on how we perceive numbers, angles, colour, time and proportions: the five senses Fively plays with, and how to get better at each of them.
Articles
Tilt
Why diagonals fool the eye
Your eye judges vertical and horizontal lines far more precisely than tilted ones. It's called the oblique effect, and it changes how to play Tilt.
Hold
How long is a second? Inside your sense of time
Without a clock, short waits feel long and long ones short, and the longer the wait, the bigger the miss. What timing research says, and how to hold steadier.