Drawing In Photoshop With A Mouse

This was drawn 'freehand' in Photoshop using a mouse. Only the brush tool and two layers were used. One layer was the line drawing. The other below it, the colour fill.  It was drawn using a desktop computer and a mouse, not an iPad or Tablet.  The idea was to drawn like you would draw with pen and paper only using a mouse.

 New Zealand Prime Minister John Key