040000 tree ef6d9d2c244628c85527307e2ab9c2da2773bd60	bidir
040000 tree d0228202d32871be97e38197b4b34537eb99572b	fifo
040000 tree 688a5f2464884234b4d069ecd9feffdc1c0c63cd	hierarchy
040000 tree 153d1708a9af71dd9ad1307e68c87db0d689de2e	producer_consumer