(eg. Aa Bb Cc)
First would be to find out all the different combinations of
these traits
ABC ABc AbC Abc aBC aBc abC abc
Then would be to make a "cross" out of them
ABC ABc AbC Abc aBC aBc abC abc
ABC
ABc
AbC
Abc
aBC
aBc
abC
abc
Then would be to 'fill in' the cross by adding them up
ABC ABc AbC Abc aBC aBc abC abc
ABC AABBCC AABBCc AABbCC AABbCc AaBBCC AaBBCc AaBbCC....
ABc
AbC
Abc
aBC
aBc
abC
abc
Hope the rest you can figure out,
Sincerely,
*diag*