I was reading this article
formatting link
and looking at the accompanying diagram
formatting link
The diagram shows a current of iD1 flowing into the X terminal of the upper current conveyor and an equal current iD1 flowing to the YZ node from below. I think as drawn, that current would actually be 2iD1, because the currrent at X is reflected to Y and to Z both, adding up to 2X at the node. Shouldn't the Z terminal of the upper current conveyor be left open or connected to one of the supplies instead of connecting to Y?