13. ... Q(h,-2)+
Chess on an Infinite Plane - Team competition! (Game 2)

The backyard-strategy
1. Gr(e3)
1...d6
2. k3
2. ...Nf6
3. g4
3. ...Gr(i5)
4.i3
4. ...Gr(k4)+
5.Kh0
5. …Gr(i2)+
6.K(h,-1)
6. ...N(h9)
7.Gr(i4)
7. …Gr(e,-2)
8.G(c1)
8. ...Q(-11,25)
9.B(d,-1)
9. ...Gr(e,-4)+
10.K(i,-1)
10. ...Q(-11,-20)+
11.K(j,-1)
11. ...Gr(h,-1)+
12.K(k,-2)
12. ...Gr(i,-3)+
13.K(l,-2)
13. ...Q(h,-2)+
14.K(l,-1)
Now black has a forced checkmate in 3 moves:
14. ...GrxR(m,1)+
15.K(m,0)
15. ...Q(m,-2)+
16.K(l,1)
16...Gr(n,-1)#
Q: “Are flank attacks good strategy (moving around and attacking from the back)?”
A: Yes, our team has won all three team games with this strategy.
It is important, however, that the Queen is present. Two Griffons cannot make a checkmate on an infinite plane when the King fled to infinity. Only in combination with the Queen can the Griffon reach a checkmate, as seen in game 3.
As soon as Queen and Griffon can start an attack in the "Backyard", a check follows the other until the checkmate. We see this development in this game starting move 9.

Good work McGoohan. You indeed played an excellent game, and at the same time developed some opening theory "The rook sacrifice" and "The backyard strategy"
And you are correct, at move 9, we were only pushed around by check for at least the next six moves until checkmate.
If you ever want to play infinite chess with the "normal" set of pieces let me know. Your ability to set up strong attacks is impressive, and I haven't been able to escape from them. You have definitely set yourself apart as one of the most accurate and precision players I've played against.
13.K(l,-2)