The tag 'd flip-flop' is only used once. This is the project:
D Flip-Flop from Nand
With 4 NAND and one invertor build D Flip-Flop
With 74HC00 4 NAND and CD4069UBH invertor we build D Flip-Flop
With 4 NAND and one invertor build D Flip-Flop
With 74HC00 4 NAND and CD4069UBH invertor we build D Flip-Flop