Tools

A.1Make and convert

• Fig. 16. 3D Photo. A depth model guesses relative depth from one photo, not distances in meters. Playground

• Fig. 17. 3D Video. A video is a string of photos, and a computer can guess how far away each part of a photo is. Playground

• Fig. 18. 3D World. A video is a string of photos from a moving camera. Playground

• Fig. 6. Model to Splats. A 3D model is usually a mesh: a net of flat triangles with colors or a picture (a texture) painted on them. Playground

• Fig. 1. Song Landscape. A song is a wave, but you can also see what it is made of. Playground

A.2Open your own files

• Fig. 27. Photo Album. A photo album keeps printed photos on thick pages. Playground

• Fig. 28. Picture Frame. A picture frame protects a photo and sets it apart from the wall. Playground

• Fig. 25. Picture Lab. The Picture lab shows a page, a photo, a GIF or a video as Gaussian splats: thousands of small, flat, colored discs, the same stuff every splash here is made of. Playground

• Fig. 26. Splash Book. A book is a stack of pages bound along one edge, so you can turn them one at a time. Playground

• Fig. 113. Molecule. A molecule is a group of atoms held together by chemical bonds. Playground

• Fig. 47. Thermal Ellipsoids. Crystallography describes an atom's average position and spread with a displacement tensor. Playground

A.3Scan and measure

• Fig. 258. Airport X-ray. An airport scanner sends a fan of X-rays through each bag as the belt carries it past, and a row of detectors measures what gets through, one line at a time. Playground

• Fig. 262. Electron Microscope. A scanning electron microscope sweeps a fine beam of electrons across a sample in a vacuum. Playground

• Fig. 261. Fruit MRI. An MRI scanner (magnetic resonance imaging) uses no X-rays. Playground

• Fig. 259. CT Explained. A CT scanner (computed tomography) turns an X-ray tube and a curved row of detectors around the object, taking hundreds of views from every side. Playground

• Fig. 260. Walnut CT. This is a real walnut, scanned with X-ray CT at CWI in Amsterdam: more than a thousand X-ray pictures taken from all around it, worked back into a volume of how dense the walnut is at every point. Playground

• Fig. 4. Room Echo Meter. Reverberation is sound that keeps bouncing around a room after its source stops. Playground

• Fig. 48. Super-Res Microscope. Ordinary light microscopy struggles to separate nearby objects about 200 to 300 nanometers apart. Playground

• Fig. 263. Thermal Camera. Everything gives off infrared light, more the warmer it is. Playground

A.4QR codes

• Fig. 7. QR Code. A QR code stores text in a square grid of dark and light modules. Playground

• Fig. 8. QR Explained. A QR code is a grid of dark and light modules with a fixed plan. Playground

• Fig. 9. QR Damage Lab. QR codes still scan when part of them is lost, because error correction can rebuild missing codewords: about 7, 15, 25 or 30 percent at levels L, M, Q and H. Playground

• Fig. 10. Triple QR. One square holds three QR codes here: the first sets each module's red, the second its green and the third its blue. Playground

• Fig. 11. Picture QR. A QR reader samples the center of each module. Playground

• Fig. 14. Video QR. A QR reader only looks at the middle of each square. Playground

A.5Sound and light

• Fig. 3. Sound in a Box. Sand on a ringing plate gathers on the lines that stay still. Playground

• Fig. 2. Chladni Plate. In 1787 Ernst Chladni sprinkled sand on a metal plate and drew a violin bow along its edge. Playground

• Fig. 29. Screen. A screen made of splats shows a video or a GIF: every pixel of the picture is a small splat whose color changes with each frame. Playground

• Fig. 5. Splat Mirror. Tap “Start camera” and each splat takes the color of its place in the picture, so the mirror shows you, live. Playground

A.6In every Splash

A.7Make and share