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Terminal: run. Derivation Graphs: (left-to-right) compact / full; (top-down) full / compact.

Help: blue = parse inside. Abbr.: WS: Workspace; Initial WS: initial heads for Merge after LEX lookup.

WS n, n = 1,2,... for intermediate stages after Initial WS. Final WS: when WS items converge on a single SO.
Bracketing: {...} (Merge). {...} (FormSet). At Spellout, {...} indicates free word order. [word] indicates word is optionally present.
Head Hd_{selection/features}, e.g. p_θ = predicate head p that seeks a θ-relevant (θR) IA from the WS. p_θ is a θ-seeker (θS).
v_see:θ:pst = head v has complement see, a θR EA from the WS and TNS. v is also a θS.
INFL seeks θR from its complement (not the WS).
Complementizer C comes in different flavors wrt. Force, .e.g. declarative C, interrogative C_Q and relative clause head C_rel.
Features, e.g. TNS pres/pst or DET the/a (shorthand for a bundle of semantic features).
Note: φ-features, e.g. 1sg, appear only at Spellout. Some words do not project, turn into features, e.g. determiners.

Words: the mechanic packed his tools

Initial WS 1: tools_his pack_θ v_pack:_θ:_pst INFL_v mechanic_the

WS 1: {pack_θ, tools_his} v_pack:_θ:_pst INFL_v mechanic_the

WS 2: {v_pack:_θ:_pst, {pack_θ, tools_his}} INFL_v mechanic_the

WS 3: {mechanic_the, {v_pack:_θ:_pst, {pack_θ, tools_his}}} INFL_v

WS 4: {INFL_v, {mechanic_the, {v_pack:_θ:_pst, {pack_θ, tools_his}}}}

Final WS: {C, {INFL_v, {mechanic_the, {v_pack:_θ:_pst, {pack_θ, tools_his}}}}}

INT/EXT: {C, {INFL_v, {mechanic_the, {v_pack:_θ:_pst, {pack_θ, tools_his}}}}}

EXT: the mechanic 3sg pst pack his tools

Spellout: the mechanic packed his tools

Parse found: the mechanic 3sg pst pack his tools

WS 1: {pack_θ, mechanic_the} tools_his v_pack:_θ:_pst INFL_v

WS 2: {v_pack:_θ:_pst, {pack_θ, mechanic_the}} tools_his INFL_v

WS 1: {tools_his, mechanic_the} pack_θ v_pack:_θ:_pst INFL_v

WS 2: {pack_θ, {tools_his, mechanic_the}} v_pack:_θ:_pst INFL_v

WS 3: {v_pack:_θ:_pst, {pack_θ, {tools_his, mechanic_the}}} INFL_v