# What do the oval and rectangular shapes in rqt_graph output signify ?

I have just started learning ROS. While analysing the output of rqt_graph I found rectangular and oval shapes in the figure. Till now what I have figured is that the rectangular boxes imply topic names and each oval shape being a node either subscribes or publishes to the topic. However there are some arrows between two oval shapes which I cannot decipher.

Can you post a screenshot or let us know the names of these two topics? (You are right that boxes are topics and ovals are nodes)