Four corners
A piece visits all four corners in a single or in more phases.
Abdurahmanović, Fadil
Mat (Belgrade), 1978
1st-2nd Prize
h#4 4.1... (2+12)
1.Kd4
fxe6
2.Kc3
exd7
3.Kb2
dxc8=Q
4.Ka1
Qc1#
1.Kf4
f6
2.Kg3
f7
3.Kh2
fxe8=Q
4.Kh1
Qxh5#
1.Kd5
fxe6
2.Kc6
e7
3.Kb7
exd8=Q
4.Ka8
Qxc8#
1.Kf6
Kg2
2.Kg7
f6+
3.Kh8
f7
4.Rh7
f8=Q#
Four corners of bK.
Abdurahmanović, Fadil
Mihajloski, Zlatko
The Problemist, 2015
1st Prize
h#5 2.1... (3+7)
1.Kf4
Rh1
2.Ke3
Ra1
3.Kd2
Ra2
4.Kc1
Kb5
5.Qd2
Ra1#
1.Qd7
Rh8
2.Kf6
Ra8
3.Ke7
Ra7
4.Kd8
Ka6
5.Kc8
Ra8#
Four corners of wR.
Hegermann, Bruno
The Fairy Chess Review, 1939
h#4 (3+7)
b) bRh6→h2
c) bRh6→b1
d) bRh6→c8
a) 1.Kf6
Kg3
2.Kg7
f6+
3.Kh8
f7
4.Rh7
f8=Q#
b) 1.Kf4
f6
2.Kf3
f7
3.Kg2
f8=Q
4.Kh1
Qf1#
c) 1.Kd4
f6
2.Kc3
f7
3.Kb2
f8=Q
4.Ka1
Qa3#
d) 1.Kd6
f6
2.Kc6
f7
3.Kb7
f8=Q
4.Ka8
Qxc8#
Four corners of bK.