test
node1
BFO:0000003
occurrent
node1->node1
node4
BFO:0000015
process
node1->node4
node2
GO:0050877
nervous system
process
node3
GO:0007600
sensory perception
node2->node3
node5
GO:0008150
biological_process
node4->node5
node6
GO:0032501
multicellular
organismal process
node5->node6
node7
GO:0003008
system process
node6->node7
node7->node2
node8
BFO:0000001
entity
node8->node1