Traditional lap pools are about 10 feet wide, though widths between 8 and 10 feet are common. (In competition pools, swim lanes are 2.5 meters wide, or about 8.2 feet.) You don't want to go too narrow with a lap pool.
The number of neurons in the brain varies dramatically from species to species. One estimate (published in 1988) puts the human brain at about 100 billion (10 11) neurons and 100 trillion (10 14) synapses.
We found that on average the human brain has 86bn neurons. And not one [of the brains] that we looked at so far has the 100bn. Even though it may sound like a small difference the 14bn neurons amount to pretty much the number of neurons that a baboon brain has or almost half the number of neurons in the gorilla brain.