You can apply a dash to any stroke (a basic, gradient, or brush stroke) so that the stroke is repeated at regular or irregular intervals along the path, just like a string of beads in a necklace. The dashes do not have to be all the same length or even be evenly spaced along the path. The spacing depends on the dash pattern you specify.
To apply a dash to a path
Select one or more paths.
In the Properties panel, in the Appearance category, under Stroke, select the Dash check box.
In the Dash field, type one of the following dash patterns:
One length If you type one number in the Dash field, Microsoft Expression Design uses this as the length of both the dash and the gap. For example, typing "36" gives you a 36-point dash followed by a 36-point gap, then another 36-point dash, and so on.
Dash and gap length If you type two or more numbers, Expression Design rotates through them. For example, typing "25 50 100" gives you a 25-point dash, then a 50-point gap, then a 100-point dash, then a 25-point gap, and so on.