Vanishing Coin Box - Magic Trick (lacquer style, 4 colours, ¥100 / 1 € / 2 €)

The GIF is an animation of the real trick, rendered frame by frame from the same coin positions the code simulates: first what the audience sees, then the same moves cut in half to show the secret.

A small black-and-gold lacquer-style box. Drop a coin on the red tray, close the lid, tip the box toward the audience for a second, open it: the coin has vanished. Tip it toward yourself and it comes back. No magnets, no springs, no moving parts: just gravity and a tunnel the audience can't see. Works with a ¥100 coin (Ø22.6 mm), 1 € (Ø23.25) and 2 € (Ø25.75).

How the trick works (spoiler)

The front half of the floor is a raised red platform with the gold emblem. It is really the roof of a flat tunnel, 3.6 mm tall, whose mouth faces you (the magician), never the audience. The tray and the tunnel floor both slope 3° down from a ridge at the tunnel mouth, so the coin stays where it is until you tip the box past about 20°. Tip it 40° toward the audience and the coin slides under the platform; tip it toward yourself and it slides back out.

Performing it

1. Hold the box with the gold emblem and the word HANMA nearest the audience (the small V-notch in the base is on your side, so you can find it by touch).

2. Show the inside, place the coin on the low red tray (your side), and close the lid.

3. Say the magic words and tip the box toward the audience, about 40°, as if "pouring" the coin to them. Set it back down.

4. Open it and tilt it slightly toward them (10° at most): the box is empty.

5. To bring the coin back, close the lid and tip the box toward yourself, about 40°.

Keep the box within about 10° of level while you show it, and don't hand it out before the coin is back on the tray.

Details

• Box 36 × 68 × 24 mm, 29 mm tall with the lid. Inside: 27.2 mm wide, red tray 31 mm long, platform 28 mm.

• Lid: gold seigaiha waves, red sun with a cream ring, cream border; a 4 mm lip drops into the box with 0.25 mm play per side.

• Body: gold rim, gold pin-line and gold plinth bevel; red tray and platform with the gold emblem and a small HANMA inlaid flush.

Printing

• One plate, Bambu Studio, A1 mini + AMS lite, 0.2 mm layers, no supports: box upright, lid face-down (the pattern is printed on the first layers).

• 1 h 48 min, 37 g in total (black 24.9 g, red 5.2 g, gold 6.3 g, cream 0.4 g, purges included).

• AMS colours: 1 black, 2 red, 3 gold, 4 cream. Colours change only on a few layers (inlays on flat faces, a 0.8 mm gold band).

• The only bridge is the flat roof of the tunnel (27.2 mm span). Use smooth PLA; a silk gold looks great for colour 3.

How it was checked

• Coin path: for each coin the code moves it from the tray, over the ridge, into the tunnel in 38 positions, lying on the real sloped floors. At every position it never touches the box (0.000 mm³), a copy 0.3 mm bigger (radius and top) doesn't touch either, and the closed lid never touches it. Play: ¥100 2.30 mm per side, 1 € 1.97, 2 € 0.72; at least 0.65 mm under the tunnel roof.

• Controls: a 27 mm coin jams (0.10 mm per side, rubs in all 38 positions); a 3.4 mm thick coin would scrape the roof.

• Hidden: once in, the 2 € coin sits 2.2 mm inside the roof edge. Rays were traced from points all over each hidden coin and over the tunnel floor toward 337 audience viewpoints (anywhere in front at ±80°, from 5° to 85° high, and from above with the box tilted up to 15° in any direction): 0 of 285,102 rays get out. Controls: from the magician's side the coin can be seen through the mouth, and with the tunnel roof only 2 mm shorter the audience would already see the 2 € coin (34 rays get out).

• Physics: with coin-on-PLA friction between 0.25 and 0.5 the coin can't move on the 3° floors by itself; it starts sliding between 17° and 30° of tilt, so 40° always works and 10° while showing is safe.

• Lid: lowered in 24 steps without touching the box; shifted 0.2 mm it still fits, 0.3 mm it would hit the wall.

• Printing: fits the 175 × 175 bed, 2 parts both sitting on the plate, no colour overlaps another, the 4 colours fill the parts exactly, no overhang over 45° except the tunnel roof bridge, thinnest coloured line 0.4 mm or more.

About this design

Designed with AI assistance and checked in code before release (see above). Pictures are 3D renders and the slicer preview, not photos. Not printed yet: makes and feedback are very welcome.

Español

Caja de magia lacada (negro, rojo, oro y crema). Pones una moneda en la bandeja roja, cierras, inclinas la caja unos 40° hacia el público y al abrir la moneda ha desaparecido; inclinándola hacia ti, vuelve. El secreto: la plataforma roja de delante es el techo de un túnel plano cuya boca mira al mago. Sirve para monedas de 100 ¥, 1 € y 2 €. Cómo se hace: 1) emblema y HANMA hacia el público (la muesca en V del zócalo queda de tu lado); 2) la moneda en la bandeja baja, tapa puesta; 3) inclina 40° hacia el público y vuelve a dejarla; 4) abre y enséñala vacía sin inclinarla más de 10°; 5) para que reaparezca, tapa e inclina 40° hacia ti. Una placa sin soportes en el A1 mini con AMS: 1 h 48 min, 37 g.

العربية

علبة سحرية بطابع اللك الياباني (أسود وأحمر وذهبي وكريمي). تضع قطعة نقدية على الصينية الحمراء، وتغلق الغطاء، وتميل العلبة نحو الجمهور نحو 40 درجة، وعند فتحها تكون القطعة قد اختفت؛ وإذا أملتها نحوك تعود. السر: المنصة الحمراء في الأمام هي سقف نفق مسطح فتحته موجهة نحو الساحر لا نحو الجمهور. تناسب قطع 100 ين و1 يورو و2 يورو. طريقة الأداء: 1) اجعل الشعار وكلمة HANMA نحو الجمهور (الحز على شكل V في القاعدة يكون من جهتك)؛ 2) ضع القطعة على الصينية المنخفضة وأغلق الغطاء؛ 3) أمل العلبة 40 درجة نحو الجمهور ثم أعدها؛ 4) افتحها وأرهم أنها فارغة دون إمالتها أكثر من 10 درجات؛ 5) لإعادة القطعة: أغلق الغطاء وأمل العلبة 40 درجة نحوك. لوح طباعة واحد بدون دعامات على A1 mini مع AMS.