A connector element for a construction system, the construction system having first and second construction elements. The first type of construction elements comprising at least one construction element having connector knobs formed on a surface thereof and arranged in a regular two-dimensional lattice. The second type of construction elements comprising at least one construction element configured to cooperate with a connector peg to form a snap connection. The connector element comprising an elongate body having first and second ends and a longitudinal axis (A1). The first end having a first cylindrical connector portion, having an inner surface configured to form a friction fit, and an outer surface configured to form a friction fit between four neighbouring connector knobs formed on a first type of construction element. A second cylindrical connector portion configured to form a snap connection with the cylindrical connector opening of the second type of construction elements.