I don't think Soundly ever claimed to be showing the curvature of the horizon as such. This would surely not be detectable from such a low viewpoint. If anyone wants to stipulate by definition that 'side-to-side' curvature can only mean the curvature of the horizon, then by that definition the video does not show side-to-side curvature. But it seems very odd to call it 'head-on' curvature when the viewpoint is opposite the centre of the line of towers, at a distance of about 4 miles, and the camera pans from side-to side along them. If we can't call this side-to-side curvature, what can we call it?