The Reachable Arc
Touch targets
Apple's 44 points and Google's 48dp exist because a fingertip is about a centimetre across and carries no cursor.
The Reachable Arc
Everything that matters lives inside the arc
A phone held in one hand can be reached only across a curve swung from the bottom corner. Apple asks for 44 points, Google for 48 density-independent pixels, because a fingertip is about a centimetre wide and arrives without a cursor.
Read the flagship pieceTwo constraints, and everything that follows from them
The signature of this publication
Constraint one
A thumb
One centimetre of skin, no pointer, and a pivot fixed at the corner of the device. Everything a player must hit repeatedly belongs inside the sweep; everything destructive belongs outside it.
44 pt — Apple Human Interface Guidelines
48 dp — Material Design
48 dp — Material Design
Constraint two
Five minutes
A commute, a queue, a kettle. The session is defined by its interruption, so the structure has to survive being abandoned mid-move and resumed a day later with nothing remembered.
Ripen on a clock · spoil if ignored
Regenerate, and end the session for you
Regenerate, and end the session for you
Six we would start with
Five Minutes
Session shape
A queue, a commute, a wait — the unit of play is minutes, and structure follows.
The Wait
FarmVille and the clock
Zynga's 2009 game made the wait itself the mechanic — crops ripen on a timer and spoil if ignored, so the game schedules the player.
The Loop
The core loop
Act, reward, invest, wait — and the fact that the loop is legible to the player is part of why it works.
First Run
The first sixty seconds
Most players who leave, leave immediately, so the opening is the most designed part of the game.
Studios
Supercell
Small independent teams with authority to cancel their own games, and a very short released list as a result.
Cow Clicker was the joke, and people played it as though it were not. That remains the most useful thing anybody has written about the form.
The arguments against
Criticism of the form arrived from inside it, on the same benches where the games were drawn.
Photo: picjumbo.com / Pexels
- Cow ClickerIan Bogost built it in 2010 as a satire — a cow, a click, a six-hour timer — and watched people play it sincerely, which is the most useful thing written about the form.
- A Casual RevolutionJesper Juul's argument that casual players are not a lesser audience but a different one, with different tolerances.
- Dark patternsWhere pacing becomes pressure, and the design vocabulary for telling the two apart.
Seven sections
Every constraint of the hand or the session, and the design that answers it
The Reachable ArcWhat one hand can actually touch.4 pieces
Five MinutesA commute is the unit.3 pieces
The WaitTime as a mechanic.3 pieces
The LoopFree-to-play as a structure.3 pieces
First RunTutorials and the first session.3 pieces
StudiosWho formalised it.3 pieces
The Drawing BoardThe arguments against.3 pieces
The colophon
Studios, critics, and toolmakers working the same seams of mobile design that this site pulls apart.
Standing support