A 90-minute block for coding, with a fan or air conditioner, if you have done this a hundred times

1 Before you start

• Set the timer where you can see it, or where you can deliberately not see it.
• Decide what you will do if you get stuck: write the problem out, then move on.
• Decide now what you will do when the timer ends. Otherwise the decision will eat the first five minutes.
• Remind yourself that you are allowed to produce something mediocre in the first pass.
• Make sure your chair is at a height where your feet are flat on the floor.

2 While the timer runs

• When you catch yourself re-reading the same sentence, stop and write down what you were looking for.
• When you have drifted for the fifth time, that is still four returns. Keep going.
• When you notice you have drifted, do not restart the block. Just come back and carry on counting from where the timer is.
• Notice the moment your hand moves toward your phone. That moment is the whole skill.

3 When it ends

• Have a drink of water before you check anything.
• Note what you actually got done, not what you meant to get done.
• Write down the question you could not answer, so it has somewhere to live.

4What to put on

a fan or air conditioner — A constant mechanical hum with no variation. The lack of change is the point — nothing in it asks for your attention.