.
├── atomic                      # atomic tasks
├── seq_composite               # sequential compositional tasks
│   ├── filter                  # tasks of the form filter{λx.F(x)}(S)
│   ├── map                     # tasks of the form map{λx.F(x)}(S)
│   └── mapfilter               # tasks of the form map{λx.F(x)}(filter{λx.F(x)}(S))
└── word_composite              # word-level compositional tasks
    ├── chaining                # tasks of the form F(F')
    ├── intersection            # tasks of the form F∩F'
    ├── land                    # tasks of the form F∧F'
    ├── lor                     # tasks of the form F∨F'
    └── union                   # tasks of the form F∪F'