A double spiral with a bar through it.

He tried to visualize a double spiral, simultaneously descending and ascending.

Both men jerked their heads skyward and saw the double spirals of two returning wings, twenty strong.

Can you curl, and do a double spiral?

This is a wooden staircase that rise 211/2 feet in a double spiral up to a choir loft.

When the process is finished, in place of the original double spiral we have two identical double spirals.

The resulting plot line can look like a figure eight or like a double spiral, if you have the two lines meeting and separating many times.

Then he catapulted upward in a double spiral and came down with both legs drawn in.

Actually, it is a double spiral, with at least eighty percent of the inhabited planets on the Main Arm.