from the science-is-fun-dept

[hitchhiker]

https://twitter.com/HLAGroupOx/status/983370740320915456

Comments

[minoanmiss]

Drawing smiley faces with lasers?

[hitchhiker]

yes :) it's a photoswitchable dye that changes colour when the light of the right frequency is shone on it.

[cjsmith]

Awwww :)