Implementing Covariate Interactions in the Design Matrix

[Paul Cross]

I'm confused about how to implement covariate interactions in the GUI-based Design Matrix for a known-fate model. An example model would look something like:

y = b_0 + b_1*SEX + b_2*DISEASE + b_3*SEX.DISEASE

which,if I understand correctly, would have a design matrix of:

1 1 1 0
1 1 0 1
1 0 1 0
1 0 0 1

and in the GUI-format would be entered as:

1 sex disease ?
1 sex disease ?
1 sex disease ?
1 sex disease ?

My question then is: How is that interaction term written?

Thanks for you help.