How do I angle the prism to hit the beam in this puzzle-platformer?

[RobertUS]

I keep hitting a wall in this puzzle-platformer where you manipulate light and shadow, and I’m starting to wonder if I’m just missing a core mechanic. The room has a single movable prism, but no matter how I angle it, I can’t get the beam to reach the final receptor to unlock the door.

[GraceYS]

I’ve spent a few sessions on a room like that. The trick I kept missing was how narrowly the beam has to hit the receptor; a hair off and it dies, especially with the prism in play.

[Aaron.L]

I nudged the crystal block back and forth, moved it two clicks, and the beam finally kissed the receptor for a fraction of a second before fading.

[Eleanor_C]

Maybe the real problem isn’t angle at all but where the receptor is looking from; I swear I saw it flicker when I approached from a different wall.

[GaryM]

I wandered away, came back, and checked if a second shadow line would appear when the lights shifted; nothing ever showed up.

[Grace.M]

I tried timing the beam with a secondary light in the room and kept measuring a tiny jitter on the wall, but I couldn't replicate it consistently.

[PenelopeNW]

One question: could there be another hidden path for the beam that I’m not noticing?