 The production of each colossal head must have been carefully planned , given the effort required to ensure the necessary resources were available ; it seems likely that only the more powerful Olmec rulers were able to mobilise such resources . The workforce would have included sculptors , labourers , overseers , boatmen , woodworkers and other artesans producing the tools to make and move the monument , in addition to the support needed to feed and otherwise attend to these workers . The seasonal and agricultural cycles and river levels needed to have been taken into account to plan the production of the monument and the whole project may well have taken years from beginning to end . 
 The production of each colossal head must <a href='been_done' title='1'><mark>have</mark></a> been carefully planned , given the effort required to ensure the necessary resources <a href='uninflect' title='2'><mark>were</mark></a> available ; it <a href='uninflect' title='3'><mark>seems</mark></a> likely that only the more powerful Olmec rulers <a href='uninflect' title='4'><mark>were</mark></a> able to mobilise such resources . The workforce would <a href='been_done' title='5'><mark>have</mark></a> included sculptors , labourers , overseers , boatmen , woodworkers and other artesans producing the tools to make and move the monument , in addition to the support needed to feed and otherwise attend to these workers . The seasonal and agricultural cycles and river levels needed to <a href='been_done' title='6'><mark>have</mark></a> been taken into account to plan the production of the monument and the whole project may well <a href='been_done' title='7'><mark>have</mark></a> taken years from beginning to end . 
Da production of each colossal head must done been carefully planned , given the effort required to ensure the necessary resources was available ; it seem likely that only tdamore powerful Olmec rulers was able to mobilise such resources . The workforce would done included sculptors , labourers , overseers , boatmen , woodworkers and other artesans producing the tools to make and move thdaonument , in addition to the support needed to feed and otherwise attend to these workers . Thedaasonal and agricultural cycles and river levels needed to done been taken into account to plan the daduction of the mdament and the whole project may well done taken yrs from beginning to end .