Bifilar Pendulum

A Bifilar Pendulum is a setup where a heavy plate (15x10x1.5 cm rectangular cast iron plate) is,suspended from a rigid support (Tshaped clamp) using two strings of equal lengths. The plate has multiple holes for attachment—two on top, two on the front, and two on the third
side. 

The strings are of equal length and are fixed at two points, with the plate swinging freely from these points.

A T-shaped clamp with split chucks is used to suspend the setup from a heavy base.

The time period of the bifilar pendulum setup depends on the mass of the plate, the length and separation of the strings, the gravitational pull, and the moment of inertia of the plate.
Adjusting any of these parameters will affect the oscillation period.