# Cellular

##### Stage: 2, 3 and 4 Challenge Level:

Cellular is an application designed to make it easy to create and explore sequences of shapes. For example, you can use it to build gnomons by painting the first two and then using the transform commands to create the rest. The pre-painted starter drawings will hopefully give you a few ideas.

There's further help below the animation.

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### How to use Cellular

• The program starts with the paint brush tool active so you can start painting a shape. Click and drag on empty cells to fill them with your chosen colour. Usually you will want to paint just one shape at a time in one colour, but you can paint a multi-coloured shape if you wish.
• The paint tool changes to an eraser if you move it over a painted cell. Click to erase. Click and drag to erase more.
• Press OK to glue the squares in the shape together and start transforming them. If you need to paint another shape, reselect the Paint brush. The transform tools always work on the the current selection which is indicated by a glowing drop-shadow. Clicking a deselected shape with the arrow tool will select it.
• To deselect all shapes, click on the background.
• If you roll over a selected shape, the arrow tool will change to a move tool. This will allow you to drag the whole selection to a new location.
• The selection has a cross-hair centre which is used as a centre for rotations and reflections. You can drag this transform centre to different locations.

#### Transform Tools

1. Move: Drag the selection with the mouse to move it. Each selection has a transform centre which may also be dragged to a new position. Shapes and transform centres both snap to the grid.
2. Turn: Click to rotate the selection through $90^\circ$ about the centre.
3. Flip: Click to reflect the selection in a vertical line through the centre.
4. Clone: Click to copy the selection. The new copy becomes the new selection.
5. Delete: Deletes the selection.
6. Join: If you select more than one shape, clicking here will join them together to make one shape. The joined shape can then be selected with one click rather than having to click on all its parts.

#### Changing the View

• Zoom In: Zooms in on the grid.
• Zoom Out: Zooms out of the grid.

#### Saving and Loading Drawings

You can save your drawing in a file by pressing 'Save Drawing'. Load it back in later with 'Load Drawing'. If you already have a drawing in Cellular and you load in a new one, you'll be given the option of deleting the old drawing or merging it with the new one. You may also find links to Cellular drawings on NRICH which you can download and use. Cellular drawings are saved as XML files with the xml extension.