The hair stroke method has become incredibly popular in recent years, I think in some part due to the trend for thick yet bushy and natural looking brows that seem to be on all the catwalks at the moment.
A very natural, lifelike looking brow can be created using the hair stroke method, which essentially is using the tattoo needle to create lots of little hair like impressions by implanting pigment in a line under the skin.
The advantages are that it does look very natural, like real hair. It is perfect for people that already have quite good hair coverage, and for those who want to fill out gaps in their eyebrows where hair is missing, because the strokes can be made to mimic the natural hair present in colour, thickness and angle. In younger skin, it can even work very well for creating a complete brow where little to no hair exists.