This is true

[hossary]

Comments

[ajvest]

If you're able to see the light, the truth emerges from the shadows

[n25052016]

Light is inside cylinder

[ajvest]

Your close. IMO, with the picture stating whats "true" then I'd have to assume there's actually 2 lights.
One Orange light being projected from the 4 O'clock position onto the cylinder resulting in a square shape shadow.
The other, is a Blue light being projected from the 8 O'clock position creating the circle shadow.
If there is another explanation for this puzzle I'd love to hear from more people and chime in on what they came up with :)