The current pipe segment
is the bottom one in the stack (on the left of the screen).
To drop it, click when the desired box on the playing grid is selected.
Once a piece is dropped the stack scrolls automatically. You can scroll the
stack without putting any piece on the grid by clicking on the "Arrow"
button or by pressing the assigned action key (default, Shift).
You can destroy wrong placed pipe segments or reveal bonuses (those marked with
a "?"), using the "Bomb" button, either by clicking it or
by pressing the assigned action key (default, Option). Both actions are allowed
only the number of times specified by the number shown in the button.
When time runs out the water
starts flowing in the pipeline; if you estimate that your pipeline is long enough
to cover the required distance, you can start the flow at any time using the
assigned action key (default, Space). A click of the mouse button will speed
up the flow.
All the three action keys are redefinable in the Preferences dialog (Keys tab).