deeply nested forms

Hey Chris i am tinkering with deeply nested forms, all is well but I can manage to render the show with all 3 forms in one ... esp the last form. when its added I get non method error and i am sure the modelling is ok , or isn’t not a hierarchical like this

I can nest B in A and C in B so calling something like @A.B.C should be fairy resolvable. hope this makes sense.