key-homescreen mapping (CSE)

1->A:1->B:1->R:1->C
Repeat K<21 and K!=0
getKey->K
If K!=0:Then
iPart(K/10->A
10fPart(K/10->B
If K!=D:Then
Output(A,B," "
K->D
End
If B<6
5B->B
B-2->B
Repeat C=B and R=A
Output(R,C,"
R+1(R<A)-1(R>A->R
C+1(C<B)-1(C>B->C
Output(R,C,"o
End
Output(A,B,"o
A->R:B->C
End
End