Object > Generative > Generate Pattern

Ideally, create and select the shape you’d like to fill with your new pattern before going to the menu command above, using the Generative pop-up at the bottom of the Toolbar or the button in the Swatches panel (Icon on the right – there isn’t a button in the Properties panel or in the Contextual Task Bar). Enter a prompt, set ‘Color & Tone’, choose between limited ‘Effects’ and set the ‘Density’ from Low to High, then click ‘Generate’.

All generated variations will be saved into a new swatch group called ‘Generated Patterns’. Any pattern swatch (including generated patterns) can be edited (by double-clicking the swatch). Remember to click ‘Done’ when finished editing.

Transforming – both the Scale Tool (S) and the Rotate Tool (R) dialog boxes include check boxes for ‘Transform Objects’ and ‘Transform Patterns’ – if the checkbox for objects is ‘off’, it’s possible to transform the patterns independant of the object (or vice-versa).