Not sure what it proves, my bro' sent this; I found them fairly quickly

Good luck - good for the brain!

Can you find the C? (Good exercise for the eyes!)

OOOOOOOOOOOOOOOOOOOOOOO
OOOOOOOOOOOOOOOOOOOOOOO
OOOOOOOOOOOOOOOOOOOOOOO
OOOOOOOOOOOOOOOOOOOOOOO
OOOOOOOOOOOOOOOOOOOOOOO
OOOOOOOOOCOOOOOOOOOOOOO
OOOOOOOOOOOOOOOOOOOOOOO
OOOOOOOOOOOOOOOOOOOOOOO
OOOOOOOOOOOOOOOOOOOOOOO
OOOOOOOOOOOOOOOOOOOOOOO
OOOOOOOOOOOOOOOOOOOOOOO
OOOOOOOOOOOOOOOOOOOOOOO

Find the 6!
9999999999999999999999999999999
9999999999999999999999999999999
9999999999999999999999999999999
9999699999999999999999999999999
9999999999999999999999999999999
9999999999999999999999999999999
9999999999999999999999999999999
9999999999999999999999999999999
9999999999999999999999999999999
9999999999999999999999999999999
9999999999999999999999999999999
9999999999999999999999999999999

Find the N

MMMMMMMMMMMMMMM
MMMMMMMMMMMMMMM
MMMMMMMMMMMMMMM
MMMMNMMMMMMMMMM
MMMMMMMMMMMMMMM
MMMMMMMMMMMMMMM
MMMMMMMMMMMMMMM
MMMMMMMMMMMMMMM
MMMMMMMMMMMMMMM
MMMMMMMMMMMMMMM
MMMMMMMMMMMMMMM
MMMMMMMMMMMMMMM