The invention provides a construct (1) comprising a number N of material types (100, 110, . . . ), wherein N is at least 2, wherein at least two of the material types (100, 110, . . . ) comprise granular material (101) comprising particles (10), wherein the granular material (101) at least defines an exterior surface (6) of the construct (1), wherein the construct (1) is self-supporting, and wherein the construct (1) is (i) self-healing or is (ii) configured for being self-healing by changing a liquid (15) content of the construct (1); wherein the different material types (100, 110, . . . ) mutually differ in at least one characteristic (19) selected from the group consisting of a physical characteristic and a chemical characteristic.