Roulete Royal

Before the pocket calculator 🧮 there was the slipstick: two logarithmic scales, a sliding stock, and a glass cursor with a hairline. It never handed you an answer. You aligned the scales, read between the graduations, and carried the decimal point yourself. Roulete Royal teaches you to drive one. There is no keypad 🎛️ in this app 📱. Every number 🔢 you produce comes off the scales. THE SLIPSTICK A real, graduation-accurate slide rule you work with your thumbs. Choose your scale pair before you touch anything, thumb the slide inside the stock, chase the cursor, and land the hairline on the target 🎯 before the clock bleeds out. The near graduations are boldly cut; the fine ones crowd toward the right index, and you learn 📖 to split a decade by eye. A detented click seats the cursor, a soft machined tick confirms a clean 🧼 landing, and a buzzer catches you mid-nudge when the read is wrong ❌. The failure textures are the lesson 📖: the slide slips a decade, the hairline sits a hair proud, the mantissa is right but the exponent is off by one. Carry the decimal point yourself — 42.7 is not 4.27 is not 427. THE SCALE CABINET 44 catalogue entries covering the scales, the gauge marks, and the operations: C and D for multiply, CI to dodge a run-off-the-end, CF/DF to dodge a re-index, A and K for roots and cubes, S, T and ST for the angles, LL0–LL3 for powers, plus gauge marks like pi and C = 1.128. The deeper entries carry what the scale graduates, what it pairs with, a worked reading, a drawn emblem, cross-links to related scales, and a one-tap 👆 "load into the Slipstick" so you can drill it immediately. Favourite the ones you keep coming back to. THE MANUAL 15 order-gated lessons, from reading the deck and seating an index through single multiply, divide, reciprocals, folded chains, squares, cubes, sines, tangents, small angles, and carrying the decimal point. The knowledge checks are honest to the instrument: you drag ✋ a hairline to a value on a live scale. No multiple choice, no keypad 🎛️. THE CASEBOOK Five long-form worked histories of the rule doing real work — trajectory margins checked on a K&E, a Fermi order-of-magnitude estimate, a Warren truss load resolved by hand, dead-reckoning on an E6B, and compound interest read straight off the LL scales. Each is illustrated with drawn diagrams and cross-referenced back into the cabinet. THE READING DRAWER Every clean 🧼 run stamps a card into your drawer: the target 🎯, the scale pair, the order you set the slide in, and your time ⏱️. Attach a reference photo 📸 of your own rule or the problem you were working, then export 📤 the stamped card to your gallery 🖼️ or share 🤝 it. THREE DESK PALETTES Manila, Celluloid, and Night Desk. The palette is the brand — every live scale, cursor, hairline and diagram 📊 is drawn in code, so the whole instrument retints with the theme. Your choice is remembered. WORKS ENTIRELY OFFLINE 📴 No account. No sign-in. No ads. No trackers. Nothing you do is uploaded — your progress 📈, your favourites, your cards and any photo 📸 you attach stay on your device 📱. A pocket slipstick you learn 📖 to drive. (3,075 characters — within the 4,000 limit)