The field inside each material is constant, which makes this structure the simplest of the multi-material structures. The only two-materials structure with this property is laminate.

The variety of effective properties of a T-structure  is defined by the volume fractions of materials  m1, m2  (these materials are in the first-rank (inner) layers), and m3 - the  material in the second-rank (outer) layer, and by the angle  a of inclination of the second-rank layer.
 

Insert
m1 = (no default value)
m2 = (no default value)
m3 =    (m3 = 1 - m2 - m3)
  a =     default value  a = 0 : Orthogonal layers.

The structure is computed sequencially. First, laminates of materials 1 and 2  are computed; the volume fraction are m1/(m1+m2) and m2/(m1+m2) , respectively. Then, the obtained composite is laminated with material 3.