Figure 2
From: Quantum error correction assisted by two-way noisy communication
The encoding circuits of the 2WNC-assisted QECCs (a). 
and (b). 
.
A boxed H represents a Hadamard gate, a pair of connected black dots represents the controlled-phase gate UCP, a pair of connected black (source) and white (target) dots represents a controlled-NOT gate UCN and 
. The dotted lines represent noisy quantum channels.
