In Young's experiment, one slit is covered with a blue filter and the other (slit) with a yellow filter. Then the interference pattern

As shown in the figure, a point light source is placed at distance $2f$ from a lens with focus length $f,$ and a screen is placed at $4f$ from the lens. The lens is then cut at the middle into two equal portions: upper half and lower half. The upper half is moved upwards by a small distance $d$ comparable to the light wavelength, and the lower half is moved downwards by the same distance $d\mathit{.}$ What is the light pattern on the screen?

In YDSE, the source placed symmetrically with respect to the slit is now moved parallel to the plane of the slits it is closer to the upper slit, as shown. Then,