This is an app available as a download from the App Store.

The patterns can be created for any yarn and for any size.
The patterns are for knitted hats, with or without a bobble.

The app is customised by the user for the gauge of the yarn, and for the measurements of the hat.

There are also options for rib (edging), and stitch options for the main body of the hat. Currently the options include stocking stitch, single rib, double rib, garter stitch moss stitch and there is the option for a cabled version.

The app can be used to create unlimited hat patterns, and the patterns are stored in a list.

The user can choose to create the pattern in metric or imperial units, and also choose the needle size system that they want to use.

The user can choose if the pattern instructions are for working flat or in the round.

The pattern is calculated to have negative ease, which is partly achieved by using a smaller needle size for the rib (edging). The amount of ease varies depending on the gauge used and the head size that the hat is for.

Note that for yarn gauge of less than 4 sts / 10cm (4”), it may not be possible to have negative ease without the hat being too small.