As far as I can tell, there's only so many ways to make something light up. Most of the time, there's a battery involved or it's plugged in to an electrical socket. Sometimes things glow in the dark. A few things have solar panels.
One would think it would be easy to tell the difference. Apparently, one would be wrong. Case in point:
Imagine a small pillow. You squeeze the pillow. Inside, a small light bulb begins to flash on and off.
Now, it's clearly not plugged into anything. There are no visible solar panels. It's flashing, not glowing. So, by process of elimination, one should quickly deduct that there's a battery in it. In fact, that's what I assumed the first time I saw it. Granted, I haven't opened it up to find out, but why would I need to? Unless it's magic, there's a battery in it.
And yet, I witnessed a woman pick it up, squeeze it, see the flashing light, and then turn to me and ask, "Is there a battery in this?"