1: Draw a box
2: Draw a circle
3: Put circle on bottom left corner of box
4: Make multiple copies of the circle across the bottom line.
5: Select all those circles and combine them
6: Copy the group to the top line
8: Copy and rotate 90° and line up on left
9: Copy and line up on right line
10: combine all circles, hold shift, select box and press Trim.
Wahla
-The Mad Signtist