RPN vs Ziro

RPN-70 HD is a complete, photo-realistic simulation of the financial hand-held calculator HP-70 from 1974. It handles loan amortization, saving plans, depreciation, and much more with ease. What users said: "Hard to find a decent calculator on iPad, try this one." "I don't normally write reviews but RPN-70 is just too fantastic to not get excited about. Apple should list this app under their Education category in the App Store and make it a must have for every college bound student. It is the best HP emulator in the market." "An incredibly well-engineered calculator app, and free, to boot!" "This is a really cool Financial calculator. Just like using the original HP-70. Accurate to the penny." Features: • Photo-realistic look based on an existing device • "Live" register view in landscape mode • Animated keys with click sound (adjustable volume) • All functions and operations of the HP-70 fully implemented • Simulation of the HP-70's computation time (optional) • Correct wrong number entries by swiping left across the display • Cut/copy/paste of display value • Visual indicators keep track of stored input parameters (optional) • Stack shown right below display (optional) • 10 non-volatile memory registers (optional) • Built-in short manual with many examples The HP-70 was discontinued after just one year. It is one of the rarest calculators, hard to find in any condition. NOTE: RPN-70 HD is a faithful simulation of a vintage HP-70 calculator, as has been verified against a real device using the examples in the Applications Cookbook section of the HP-70 manual. In certain cases, what may appear like a bug of the app is actually an idiosyncrasy of the HP-70. IMPORTANT: The HP-70 requires exactly three input parameters from the top-row keys, at least one of them being either "n" or "i". In other words, you can't use PMT, PV, and FV as input parameters simultaneously. A version for the iPhone named "RPN-70 SD" is also available. Visit the website: www.cuveesoft.ch

Time, told in ones and zeros. Calm, delivered in soft hiss and rain. Ziro is a tiny piece of digital art that hides a binary clock and a white-noise machine inside one quiet screen. Open it on your desk while you work, set it by your bed while you sleep, or just leave it glowing on a spare phone as ambient room decor. No accounts, no ads, no nagging notifications — just zeros, ones, and the sound of focus. A BINARY CLOCK FOR THE TECHNICALLY CURIOUS Every column of dots is a digit; every dot is a power of two. Ziro turns the time of day into the same on/off language your computer speaks, making it an instant conversation piece for developers, engineers, students, and anyone who likes their gadgets a little geekier. Glance at it for a second and you get the time. Stare at it for a minute and you start to feel the pattern. It is the kind of clock that quietly teaches you something every time you check it. A FRIENDLY WAY TO LEARN BINARY Ziro doubles as a tiny lesson in how computers actually count. Watching the dots light up and reset teaches place value and powers of two more naturally than a textbook diagram. It is handy for students learning binary numbers for the first time, parents looking for a simple computer science explainer for kids, teachers wanting a visual aid, or anyone brushing up before a coding interview. There are no quizzes and no lessons to complete, just a clock that happens to explain itself. A POMODORO TIMER WITH WHITE NOISE BUILT IN Ziro pairs a classic Pomodoro work-and-break regime with a built-in sound machine, so deep work sessions arrive scored. Pick an interval, hit start, and let the soft hiss of white, pink, or brown noise mask office chatter while the binary dots quietly count down. Swap in rain, wind, or steady ambient hum to soothe a restless mind at bedtime, soundtrack a morning meditation, or help a baby drift off. Everything runs offline, so the soundscape never stops to buffer. A MINIMAL DESIGN, MADE AS AN ART PROJECT Ziro started as a small art project about how little a clock really needs to be. The result is a stripped-back interface with no menus to learn, no streaks to keep, and no dashboards to optimize. Just light, time, and sound — composed to feel calm on a nightstand and at home on a standing desk. Pick a color, dim the dots, and let the room change around it. FREE FOREVER, POWERED BY DONATIONS Ziro is completely free, with no subscriptions, no paywalls, and no advertising. If the app earns a spot in your daily routine, an optional donation inside the app keeps it independent and helps fund the next quiet feature. Download it, share it with the nerd in your life, and turn any screen into a small piece of moving art. Less interface. More time. Ziro. Ziro is free to download.