Forces on lines

Gigantic forces pull on lines
when the heavy sails are moved.
A metal ring the block entwines
whose wood is three times grooved.

Such a trick to share the forces
on the lines was used to lift,
as is seen in older sources,
heavy blocks of stone to shift.

Online forces nowadays
are used to shift, to drag or pull
money, facts or dreams in ways
no head once could be so full.

Nevertheless we have to hope
that our human heads can cope.