Symmetric relations.
Signs of the corresponding functions are different.
Function interaction: 1 ↔ 6, 2 ↔ 5, 3 ↔ 8, 4 ↔ 7.

Information from the ego block is interacting with the partner's superid block. Information from function 1 falls on the partner's activation function 6. The partners are partially complementary on the dimensionality with bias towards functions 1 ↔ 6, which results in intensive information supply to the function 6. Such an activation is useful when there is a need to shake-up, encourage or activate the partner but it could be uncomfortable for long communication because of the possible overload of the function 6.

Interaction between functions 3 ↔ 8, 4 ↔ 7 does not have constant painful effect on the superego block of each of the partners for the same reason as for the duality relations - because of self-centered nature of id blocks activity. However some clashes of these blocks are possible if there is overlapping of partners' areas of interests involving the superid and superego functions, for example, in a professional situation. 

The Partners are complimentary with respect to mental/vital track, that is, all mental track function of one of the partners are located in the vital track of the other partner. The partners have different rationality which causes a bit more difficult understanding compared to the duality relations.