Draw all non-isomorph graphs with 7 knots in our course we had to draw all non-isomorph graphs with 7 knots without loops. Since this is hard to explain I'll add an Image. !My notes The blue written part is accepted by the tutor and the pencil written part is what I think should be included. I'm not sure if the tutor forgot to include those or if there is a reason why not since they seem to have a different structre than all the above. In case the picture is hard to read here I uploaded it somewhere else too: < Edit: It has been suggested that the correct way to put it was "I think the English phrasing would be to draw all non-isomorphic trees on seven vertices" Thanks!

The intuition is that two graphs are isomorphic if one can redraw one to get the other.

In your case, your left-most graph is isomorphic to graph $1$, since you could "straighten" that horizontal edge to a vertical edge to get graph $1$. Similarly, your middle graph is isomorphic to graph $3$ and your right-most graph is also isomorphic to graph $3$ (turn it upside down).