When a tripwire that is connected to a block next to a dispenser (see picture) is stepped on, the dispenser gets triggered three times (dispenses three items)

additionally, walking forwards or backwards along the tripwire will continue to trigger the dispenser, causing three items to be dispensed for each block travelled along the wire

Picture Description
Walking towards or away from the dispenser linearly, along the tripwire, causes 3 items to be dispensed each meter (one block) travelled