Movable Polygons without visible point?

I was looking at this activity, and wondering if anyone knows how you are able to move the number squares without having a visible point to manipulate. I can’t seem to replicate it, although I can copy the graph and it works fine, so may just need to use it as a template.

It looks like the polygon, graphic, and point are all linked to the same sliders for the coordinates of the center. So when one of the three is moved, all are updated with new slider values. Great idea!

I tried it independently and it doesn’t work.

Strange. Maybe the order the items are created changes their independence?

I’m pretty sure this is an internal feature. You’ll see this behavior in some activities created by Desmos, like the Scaling Machines activity. I think in this case, Tim may have worked in collaboration with Desmos to create these activities. This sometimes happens with the Challenge Creator too.

I take back what I said. @Susan_Lauer was right, the draggable image controls everything. You just need to make sure you have the image set to draggable in the options menu for that image. Here’s a basic example.