Feature spec
Goal: Send a clear invoice after finishing a job.
- Add a client, line items, a due date, and payment instructions.
- Preview the total before exporting a PDF.
- Keep an editable draft if export fails.
This is a multitouch synth instrument
$2.99 · In-app purchases
Evidence scope: No current overall US chart position is available. Category-chart positions shown in discovery are a separate scope. Revenue is a directional model estimate, not verified earnings.
A product spec, screen plans, and build steps for your coding agent.
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Combine features and design from your favorite apps.
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What should your app do differently? Your note travels with the kit so your coding agent builds around your idea.
A product spec, phased build plan, differentiation notes, and screen references.
Illustrative example: an invoice app for independent contractors. Your kit is tailored to the app you choose; this is not its generated content.
Goal: Send a clear invoice after finishing a job.
Invoice editor: Client at the top, editable line items in the middle, total and preview action at the bottom.
States: Empty draft, validation errors beside each field, exporting, and a retry action that preserves the draft.
Hypothesis: Contractors need faster repeat invoices more than more templates.
First experiment: Test duplicating a previous job with five contractors. Watch where they hesitate before expanding the feature set.
The full kit adds a phased build plan, evidence notes, tool prompts, and implementation guidance. It is a plan for your coding agent, not a finished app.
Usage: Mechanics are fair game; never reuse the original name, branding, assets, or verbatim copy.
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Good fit for mobile-first iOS and Android prototypes with managed app scaffolding.
Rork plan preview for Theremin Synth - Record & Loop: map the core Music workflow, choose the smallest differentiated feature set, define the data and monetization boundaries, then prototype the riskiest user journey first.
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These are generated suggestions, not verified review quotations. Check current App Store reviews and speak with users before treating a possible gap as a requirement.
Hypothesis 1
Assumption to check: Limited sound customization options
Validate with people who use this workflow before building.
Hypothesis 2
Assumption to check: No offline access for recorded loops
Validate with people who use this workflow before building.
Hypothesis 3
Assumption to check: Confusing loop management interface
Validate with people who use this workflow before building.
Hypothesis 4
Assumption to check: Lack of tutorials or onboarding
Validate with people who use this workflow before building.
Original App Store material. Ratings and screenshots describe the existing app, not proof of demand for your version.
This is a multitouch synth instrument. Play it by touching and swiping the screen, changing the waveforms and sliding the effects to create anything from traditional sci-fi theremin sounds to deep scuzzy soundscapes. Use the looper controls to record, loop and overdub layers. Then if you wish to save or share your recording, hit the download button to send your wav file to other compatible apps like Messages, Email, Dropbox etc. The original Theremin went live in 2014 on the web at femurdesign.com/theremin. Over a million hits later and hundreds of requests for a record button, I have redesigned it. Now the Theremin is ready for you to experiment with. Happy playing! -- SPECIFICATIONS -- • Record, loop and overdub options. • Multitouch allows up to 8 tones to be played simultaneously with your fingers • 3 sliders: delay, feedback and scuzz • 4 waveforms: sine, square, triangle and saw • No internet needed, works both online and offline • Download the loop as a .wav file • Loops can be shared with other apps like Mail, Message and more. • 1000+ installs • Compatible with iOS versions 8 - 10 • Optimized for iPhone, iPad & iPad Pro -- REVIEWS -- Gizmodo "Just mess around! Twiddle those faders! Swipe and click with reckless abandon! Turn the volume all the way up, give the dog a panic fit, and make your neighbours think the street's being invaded by giant cabbage people from planet Zok. Trust me, this will never get old.” Dangerous Minds “New online theremin simulator kind of sounds cooler than the real thing. Check it out and annoy your co-workers.” Mashable “Messing around with this virtual theremin is completely addicting” -- CONTACT -- To find out about my other musical app projects, please go to femurdesign.com and share your loops with me on Facebook and Twitter. Facebook: facebook.com/femurdesign Twitter: @femurdesign For any queries and support contact me here: femurdesign.com/support
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Plan a focused first version with your coding agent. These are planning assumptions, not a delivery guarantee.
Choose one audience and one core workflow. Use the kit to agree on its screens, data, and acceptance criteria before building.
Decide which secondary features, integrations, and platform support can wait. Your version does not need to reproduce everything in the original.
Validate external services, specialist technology, data access, and ongoing costs for your chosen scope.
From the Build Kit assessment.
A reliable timeline needs an agreed scope and a technical check. Ask your agent to estimate the phases in BUILD_PLAN.md after that review.