70ft - 21m
Q
60ft - 18m
WR
50ft - 15m
RBHQ
40ft - 12m
YGSOT
30ft - 9m
JBPNXR
20ft - 8m
OHTTMNYZ
15ft - 4.5m
NJMEGXTBHW
10ft - 3m
ISUROPOVCP
7ft - 2.1m
LELBOGDFTMP
4ft - 1.2m
QVKKXTBVXCKJQKCSH

Chart copied from lance. That link is gone, and I've been using it for years, so I made a JS copy. I look at it from 130cm.

Stereograms?