A polyamide is prepared by reacting at least one dinitrile and at least one diamine with water at a temperature from 90 to 400 C. The combustion chamber surrounds the cooking chamber at least in sections at the sides and the combustion chamber is open to the cooking chamber. In addition, the pull bar can be detached from the bottom rail when not in use, thereby enhancing the aesthetic quality of the window covering. The multiplexer circuit may include a switching-element coupled to an output node of the capacitor element to couple the signal to a column. The upper layer has a thickness of 3 nm or more and 6 nm or less.