What error is present in Figure 2.6 of the textbook?

2.7 Symbols Used For Logic Gates When they design circuits, engineers think about interconnecting logic gates rather than interconnecting transistors. Each gate is represented by a symbol, and engineers draw diagrams that show the interconnections among gates. Figure 2.6 shows the sym- bols for nand, nor, inverter, and, or, and xor gates. The figure follows standard termi- nology by using the term inverter for a gate that performs the Boolean not operation. nand gate nor gate inverter and gate or gate xor gate Figure 2.6 The symbols for commonly used gates. Inputs for each gate are shown on the left, and the output of the gate is shown on the right