App studio, Tokyo

Stems

Stems is an app studio in Tokyo. Apps grow here slowly, one stem at a time.

001 KOKEMUSUMoss garden for time away from your phoneiPhone · On the App StoreKOKEMUSU app icon: a green mound of moss on a dark ground002 yawpLoops that drift into musiciPhone and iPad · Out Oct 22yawp app icon: one hill with a bead on its crest003 Coming up
  1. 2026 Sep
  2. Oct
  3. Nov
  4. Dec
  5. 2027 Jan
Today, Oct 5

001 KOKEMUSU

A moss garden that grows while your phone is down.

Call the rain, and the apps you chose stay locked until it stops. The moss drinks and grows. Every ten minutes of rain fills a cup of rainwater for new pots and moss. Stop early and the garden only dries a little.

Planted
2026.09.17
Launched
2026.10.02
Platform
iPhone
Made by
Stems: concept, design, sound, code
Status
Free on the App Store
  1. Opening screen: a bowl of moss on tatami and the words Set the phone down. Grow moss.01Set the phone down
  2. How it works: the moss grows, the apps you chose stay locked, rainwater collects02When you call the rain
  3. Choosing a vessel for the first moss: Edo glass or Kiyomizu ware03Your first pot
  4. The garden while it rains, with the moss fully grown and 25 minutes left04The garden, raining
  5. Rain panel: 25 minutes left, rainwater collected, and lengths from 15 minutes to 2 hours05How long it rains
  6. A glass bowl of Sugi-goke on a cloth, seen up close06A pot up close

Vessels and mosses

  • Sugi-goke in a round lapis-glazed pot on the stand
    Kiyomizu ware
    Sugi-goke
  • Hai-goke in a shallow oval iron-glazed pot on the stand
    Mashiko ware
    Hai-goke
  • Tama-goke in a rectangular unglazed pot on the stand
    Tokoname ware
    Tama-goke
  • Sugi-goke in a round glass bowl on the stand
    Edo glass
    Sugi-goke
  • Tama-goke in a tall glass jar on the stand
    Otaru glass
    Tama-goke
  • Hai-goke in a square glass vessel on the stand
    Hizen vidro
    Hai-goke

002 yawp

Draw a hill. The notes follow.

An instrument for people who think they can’t make music. Every voice is a loop of its own length: draw a hill over it and the notes follow. Let the loops drift apart, and minimal techno and ambient happen. Twenty-two voices, every one synthesized.

Planted
2026.09.29
Platform
iPhone and iPad
Made by
Stems: concept, design, sound, code
Status
On the App Store October 22, 2026
    1. Voices drawn as hills over their loops, notes sown along the baseline01Draw a hill
    2. Keys, bell, glint, arp and drone on loops of different lengths02Loops of their own lengths
    3. A tall room drawn in hairlines, the sea moving beyond a window03The song as line art
    4. A fader for every voice, and knobs for low, mid, high, echo, tide and room04The mixer
    5. The tuner: twelve note names under one needle05Tune the whole song
    6. yawp in night mode: pale lines on dark paper06Night

    Film

    yawp, played: a song built by hand on an iPhone