A little experimental animation of a main panel in the main stained glass window in St George's Tron Church (SGT), Glasgow.

I had initially considered tracing it in Adobe Illustrator, but instead worked directly with the pen tool in Adobe After Effects. The main effect is created by applying Trim Paths & animating the End point value of each path (from 0 to 100%). Great use was made of pre-comps and reflection in horizontal and vertical axes of symmetry - apply a Tranform effect, uncouple the dimensions and turn the scale value from the default 100 to -100 depending on which axis you wish to reflect in.
(So where you had an element appear in all these - ie 4 times, they would have values of (100,100), (100,-100), (-100, 100), (-100,-100)).

The St Andrew's cross arms have a circle fill - this was replicated using the Repeater function alongside two rectangles, pre-comp'ed and then replicated in rotation.

After the design has been animated, the actual real image in faded in for full effect. To fill the 1080 by 1920 typical video size, the main composition was duplicated left and right and the timing offset for additional interest (with slight colour desaturation and a Gaussian blur to enable the eye to focus on the main design instance in the middle).