A slide lever on the bridge of the eyeglasses pushes the fluid forward or backward to alter the shape of that membrane, changing the focal distance depending on what the user is doing.

The engineer said, "Slide-rule, go!" The dog built a suspension bridge.

Unusually deep front to back for a small lathe the saddle carried an almost boring-table sized T-slotted cross slide fitted with a "bridge bracket" at the front.