Utilities panel > Utilities rollout > More button > Utilities dialog > Strokes
The Strokes utility lets you launch commands by dragging left-button mouse patterns in a viewport. When you launch the Strokes utility, a modeless dialog appears containing a single Draw Strokes button. When the Draw Strokes button is active, you can define and use strokes with the left mouse button.

The Strokes system is also available as an option for the middle mouse button that doesn't require the utility or the modeless dialog. This option can be found on the Viewports tab of the Preferences dialog. For details, see Strokes.
Example: To define a stroke pattern for Arc Rotate:
On the Utilities panel, click the More button, and choose Strokes from the list.
Hold down the left mouse button and drag the mouse straight down from top to bottom, then release the mouse button. The length of the stroke doesn't matter, but the direction does.
A dialog appears asking you to define the pattern or continue.
Choose Arc Rotate from the Command To Execute list and then click OK.
Example: To turn on Arc Rotate using the Strokes utility:
In any viewport, hold down the left mouse button and drag the mouse straight down from top to bottom. The length of the stroke doesn't matter, but the direction does.
As you drag the mouse, small X's appear, displaying your stroke. When you release the mouse, a 3x3 grid appears briefly, and then the program switches to Arc Rotate mode.
If a Stroke Not Found message appears, click Continue, and then repeat step 2.