Proof: (1) because of ABC-a.
1
B
1
C
1? It is a straight triangular prism, so CC
1 easy plane ABC,
And the AD plane ABC, so CC
1 easy AD.
And because of AD Yide, CC
1
, German plane bcc
1
B
1
, cc
1 suspected DE=E,
So easy plane bcc
1
B
1
. ? The front of the plane,
So this plane is a translocation plane.
1
B
1
.
(2) Because of one
1
B
1
=A
1
C
1
F is B.
1
C
1? The midpoint of, so a
1
F yi b
1
C
1
.
Because CC
1 easy plane a
1
B
1
C
1
And one
1
F plane a
1
B
1
C
1
,
So CC
1 yi a
1
F.
Because CC
1
，B
1
C
1 plane bcc
1
B
1
, cc
1 suspected b
1
C
1
=C
1
,
So a
1
Easy plane bcc
1
B
1
.
Seeing the BCC of AD Easy Plane from (1)
1
B
1
, so one
1
F chair AD.
Also called AD plane ADE, a.
1
F plane ADE, so a
1
F seat plan elevation