Beam Suit

A laser beam is not a ray. It has a waist, it diverges, and every lens you put in front of it changes both. Beam Suit is an optical rail where you can see 👀 that happen. THE RAIL Lay out a train: lenses of any focal length, positive or negative, an iris, a mirror. Seat each element at its own position along the rail and the beam redraws immediately — the envelope narrows, crosses its waist and opens again exactly where the maths says it should. THE NUMBERS THAT MATTER 🔢 Under the rail sit the figures an optics bench actually needs: the beam radius at the current plane, the waist radius, the Rayleigh range, the far-field divergence in milliradians and the spot diameter. Change the wavelength and every one of them moves with it — a 632 nm helium-neon line and a 1064 nm infrared beam behave differently through the same lens, and here you see 👀 how differently. TUNE, DON'T GUESS Every element on the rail can be tuned in place: shift it along z, change its focal length, watch 👀 the waist walk. Building a telescope from an f50 and an f-75 stops being a formula and becomes something you can watch converge. SAVE THE TRAIN 💾 A layout you like is saved with all its elements and their positions, so a setup can be reproduced later or used as the starting point for the next one. THREE WORKING SKINS Cyanotype for a nineteenth-century drafting table 📋, whiteprint for blue ink on drafting cream, and darkroom for cold cyan trace on graphite. Optional haptic ticks as you drag ✋ along the rail, and the numeric readout can stay open or fold away. Everything is computed on the device 📱 — no account, no connection, nothing sent anywhere.