Begin with a 800x600 image. Select a 350x425 rectange, Render clouds with yellow and brown.

Oil painting effect with max courseness and brush size.

 

Stylize -> Relief (about 120)

Render -> Shape3D as shown below.

 

Adjust Hue and Saturation until you have wood color.

 Select object,

Add new layer

 .Render clouds.

 

Stylize -> Relief.

Adjust to Black and White.

Change Layer Property to Multiply with Opacity 144.

Merge layer down and distort with Polar Inversion.

Add other mouse features as you see fit.