Changing the value in the Seed field will generate the corresponding input to the Input field.
Pressing the Download button will download the inputs for seed values seed, seed+1, ..., seed+#cases-1 at once.
You can change the size of the warehouse D or the number of obstacles N by changing the value in the "fix D" or "fix N" fields.

By running your program locally against the generated input and pasting the output of your program into the Output field, the visualization results will be displayed.
Pressing the ▶ button starts animation.
By pressing the Save as PNG button, you can download the visualization results.

The lower part of the visualization result shows the status of the warehouse.
Each colored square corresponds to a container, and the one surrounded by a black border represents the last place brought in or transported out.
By pointing the mouse cursor over each square, the coordinates are displayed in a tooltip.

In the container storage phase, the upper part of the visualization result shows which containers have already been brought in.
Gray containers indicate already brought in; other containers indicate those arriving in the future.
The container with the black border is the one that has just been brought in and whose storage square is being selected.
In the container transport phase, the containers transported out are displayed at the upper part of the visualization results in the order in which they were transported out.

By checking the "manual mode" checkbox, you can play the game manually.
Click on the square where you want to store the container or the container you want to transport out.
If you make a mistake, you can undo it by pressing the Backspace key.