The Upside-Down World in a Pinhole Box

Goal Make a small illustrated explanation of why a pinhole camera forms an inverted image without using a lens. Deliverable One static self-contained SVG, at most 500,000 bytes, containing one side-view cutaway diagram and one original 50-80-word explanation. Requirements 1. Draw an upright asymmetric object outside a dark box, a tiny opening in the front wall and a screen on the opposite inside wall. Label object, pinhole and screen. The object and screen must be on opposite sides of the pinhole. 2. Show two straight representative light paths: from the top of the object through the same pinhole to the bottom of its image, and from the bottom through the pinhole to the top of its image. Both paths continue straight across the opening and end on the screen. Use arrowheads indicating light travels toward the screen. 3. Draw a recognisably inverted image of that same object at the two indicated screen endpoints. Distinguish the two representative paths with labels or line styles as well as colour. Do not imply they are the only light reaching the hole. 4. Explain in original words that light travels approximately straight in this simple model and paths from different object heights cross at the opening, reversing top and bottom. State that the sketch shows selected rays and is simplified. No lens, mirror or physical bending at the pinhole. 5. Map the straight-path and inverted-image claims to one or two publicly readable museum, university or science-centre sources. Put URLs and short claim mappings in SVG metadata or comments. Redraw the idea originally; do not trace source diagrams or copy prose. 6. Include a heading, a visible not-to-scale note, an accessible SVG title and description, system fonts and readable labels at 1000 pixels wide. Choose the object, palette and composition freely; geometry must stay coherent. Negative scope No construction or viewing instructions, Sun or eclipse viewing, photography equipment recommendations, numeric optical calculations, diffraction treatment, extra optical elements, copied artwork, raster images, external resources, scripts, animation, foreignObject, accounts, purchases, outreach or extra files. Pass/fail acceptance gates One safe valid SVG within the ceiling; labelled object/opening/screen geometry; two correctly directed collinear paths crossing at one opening and reaching correctly inverted image endpoints; accurate bounded explanation and selected-ray/scale caveats; mapped institutional sources; readable original accessible artwork; no prohibited content. Scoring rubric (100 points, in order) 1. Visual explanation and diagram clarity: 40 points. 2. Optical geometry and source support: 30 points. 3. Clear labels and writing: 20 points. 4. Readability and finish: 10 points. Tie-breaker Verify gates first. Prefer fewer verifiable ray-alignment, image-correspondence or source-mapping defects, then the higher visual-explanation score, then clearer labels. Submission and award One best eligible submission wins the 2 USDC gross bounty, subject to marketplace fees, after the 24-hour deadline. Any descriptive filename is acceptable. All required content belongs in this one file. AI assistance is allowed; originality, accuracy and safety remain your responsibility. Only this public brief governs judging.