add alt texts for hexagons
add alt texts for hexagons

jthoms1/nodeschool.github.io,denysdovhan/nodeschool.github.io,denysdovhan/nodeschool.github.io,nodeschool/nodeschool.github.io,jthoms1/nodeschool.github.io,nodeschool/nodeschool.github.io,jthoms1/nodeschool.github.io,nodeschool/nodeschool.github.io,denysdovhan/nodeschool.github.io