STEM
SpokeForge
How does a bicycle turn one push of your legs into a wheel spinning four times over? Gears. The front teeth divided by the rear teeth is the gear ratio - how many wheel turns you get per pedal - and it sets everything: how hard the pedals are, how far one push carries you, how fast you go. Predict the ratio, then build your own gear in the workshop. Real, tiny, deterministic maths - no internet. Ages 9-14.
▶ Play it nowBuilt for sittings of about 20 minutes on the screen. That is our design budget, not a measurement.
Meet your mentor
Every Spark & Anvil app has a friendly mentor character that demonstrates, asks, and patiently scaffolds learning.
Mentored by Cadence
#a8551f Characters who teach
Meet the cast
SpokeForge's crew ARE the parts that make a bicycle a machine - the cast IS the curriculum: each character's job IS one ratio the rider feels. Chainring is the big front gear - the more teeth it has, the harder and faster the gear it sets. Cog is the little rear gear - the more teeth it has, the easier the gear, for spinning up hills. Cadence, the mentor, is the rider's own spin, and reminds the crew that speed is only ever distance-per-pedal times how fast you turn. Brake trades a small pull at the lever for a big squeeze at the wheel - another ratio, working the opposite way. Nothing leaves the device.
Chainring
The big front gear - the more teeth it carries, the higher the ratio, so a bigger chainring means a harder, faster gear
Cog
The little rear gear - the more teeth it has, the LOWER the ratio, so a bigger cog means an easier gear for climbing
Cadence
The rider's own spin, who keeps the crew's one rule straight: speed is distance-per-pedal multiplied by how fast you turn the pedals
Brake
Trades a small pull at the lever for a big squeeze at the wheel - a lever ratio working the opposite way, force over control
What's inside
Learning goal
How does a bicycle turn one push of your legs into a wheel spinning four times over? Gears. The front teeth divided by the rear teeth is the gear ratio - how many wheel turns you get per pedal - and it sets everything: how hard the pedals are, how far one push carries you, how fast you go. Predict the ratio, then build your own gear in the workshop. Real, tiny, deterministic maths - no internet. Ages 9-14.
Mentored by Cadence — no data leaves the device.
How SpokeForge handles your kid's data
- ✅ All progress, settings, and AI-generated content stays on the device
- ✅ No analytics, no tracking, no third-party SDKs
- ✅ Free — no ads, no in-app purchases
- ✅ No personal information collected from children — in line with COPPA (updated by the 2026 FTC amendments)
- ✅ No chat with strangers — play-together rooms use a short code and preset emotes, never typed messages