Here’s a more detailed description for those that like to read up: https://rarehistoricalphotos.com/nasa-spiders-drugs-experiment/
Curiously enough when a similar experiment was first performed decades earlier the original intent was to get the spiders to weave their webs during different times of the day, rather than alter the pattern.
Would have been interesting to see what happened with alcohol, ecstacy, cocaine, heroin, etc. The last one might have just been a blank square though.