This tutorial will show how to make a thatched roof, a straw roof.
The roof will look ok from a distance and is quite ugly in close up.

Follow up:

For this tutorial I started with a pyramid (converted to polygonal).
To avoid problems with "partings" further on I have cut the top of the object. Like this.

Add a hair collision tag to the object and click on Add Hair with the object selected.
Make the hair quite short as in the above image.

Now you need to relax the guides. I do that hitting the "G" key several times. Do this until the hairs run parallel to the roof. (Like in the image above)
With the Cut tool (scissors) you shorten the last row at the bottom, this will make better results.

Now this is very important to avoid heavy frustrations. (you probably encountered this just a minute ago)
In order to edit hair in the current relax position you must hit the "Set As Dynamics" regularly. This will fix the guides in current position. After you are happy with the position of the guides disable the dynamics in the Hair tag, otherwise the roof will behave strangely in animations.

Hairs tab. To get a full roof set the count of hairs to 20000 or higher.

The Texture.

Color.
Lets start with the color. I chose a beige brownish color to start with. Then I made the tip very dark. This is not enough to get the best results so I made a variation in Saturation and euh "V" off 5% and 10%, this will make each straw just darker or lighter than the next one.

Specular.
Usually when not making hair I put the specular on very low values, this goes for straw but also for grass.

Thickness.
The straws should be of equal thickness at their beginning and end and there can be a slight variation between straws.

Last thing is a very small amount of Frizz. Other channels like clump can be worthwhile to try as to get some variation.

That is it I think.
Don't come to close to this roof as it is not intended for close-ups.

Come on farmers show me your cottages!