But to do the tasks correctly, your brain is fundamentally making a series of comparisons, incorporating visual and haptic sensory information. The key here is that the white space of the cards prevents you from putting the two lines exactly next to each other.
What if you just hold the cars facing each other so the lines are just short of touching? Then you can see the lines pretty much side-by-side.
Yes, I am smarter than a fifth grader.