Adjustment to equilibrium in Cournot model with 2 firms In pg. 509, of Hal Varian's Intermediate Microeconomics Ch. 27, writer discusses the Cournot equilibrium.

In the figure, the reaction curve of firm 1 f1(y2) was steeper than firm 2 f2(y1). 

When we started from the point (y1t, y2t), we were able to reach the stable equilibrium. But what if f2(y1) was steeper than f1(y2)? I cannot find any adjustment process. Can such condition be viable? If not, then why?![Adjustment process when f1(y2) was steeper than f2(y1)]1
The trick is to draw the whole reaction function—including the part that coincides with the axis. Hopefully these figures make it clear: