This is a well known optical illusion in which rotation appears to be vertical motion. There are several aspects of the barber pole design which make the illusion more effective, including having multiple stripes, making the stripes different colors, and using rotation. We will strip these things away in order to see what is happening…
Tag: geometry
Metric space
We take for granted that we can measure distances. Most people take for granted that we can represent physical space mathematically and calculate distances between pairs of points. We generally think of ourselves as living in R3, or 3D Euclidean space. Since this is how we represent physical space, it’s generally the most useful (though…
Equality, equity, equivalence, identity, indistinguishability, isomorphism, resemblance, congruence, and similarity
While the title of this post might as well be a thesaurus entry, my purpose here is to investigate the differences between these concepts and how they operate in different contexts. Mathematical equality The reader is almost certainly very familiar with the equals sign or = used in math. Many of us first encounter it…
The geometry of body plans
Let’s talk about evolution. All living organisms require a way to acquire and metabolize food, a way to respirate, and a way to reproduce. Many single-cell organisms like bacteria can eat by engulfing food within their cell, a process called phagocytosis. Algae and plants are autotrophic, meaning they produce their own food. Some simple animals,…
thoughts on mind 