Add link to Tetris implementation#

README.md

@@ -16,7 +16,7 @@ Consider the problem of generating [Tetris](https://en.wikipedia.org/wiki/Tetris
   <img width="400" src="docs/images/tetris_flows.png" />
 </p>
 
-We could define a reward function $R(x)$ as the number of cells occupied by pieces, for instance. The goal of training a GFlowNet on this task would be to discover (sample) diverse solutions (boards with pieces) with high rewards. This represents an intuitive yet complex problem where GFlowNets can be used. Many problems in scientific discoveries, such as the inverse design of proteins, molecules, or crystals share similarties with this intuitive task.
+We could define a reward function $R(x)$ as the number of cells occupied by pieces, for instance. The goal of training a GFlowNet on this task would be to discover (sample) diverse solutions (boards with pieces) with high rewards. This represents an intuitive yet complex problem where GFlowNets can be used, which is [implemented in this library](https://github.com/alexhernandezgarcia/gflownet/blob/ahg/313-update-readme-components/gflownet/envs/tetris.py). Many problems in scientific discoveries, such as the inverse design of proteins, molecules, or crystals share similarties with this intuitive task.
 
 ## Main Components of the GFlowNet Library