On iPhone: screenrecord. Take screenshots every couple seconds. Overlay images with 50% transparency (I use Procreate Pocket for this part)

On Android: Take a look at the URL, see the text in plain-text :)

	▲	catlifeonmars 4 days ago \| parent [-]
		Nice. I did not think to look there.

A single photo is good enough as long as the exposure time is long enough to capture the motion blur.

	▲	catlifeonmars 4 days ago \| parent [-]
		If I had another camera then yes, that would have been easier. In my case I only had the one mobile device and I don’t think screenshots support long exposure.