What can be reason of such a behaviour?
a bit more information would be helpful 
So what is your aim?
It seems that the alphabet is a texture which is applied onto a plane.
It seems that the texure is shown several times on the plane, and i guess you would like to have it shown only once.
Is the texure supposed to be shown around the rectangle, or should it be displayed inside of the rectangle?
For me it seems, that you have modeled the geometry in blender/3dsmax/maya and exported/imported it into jme.
Independent from the position of the texure (if it should be shown inside or outside of the rectangle) it seems to be a problem with the uv-coordinates of the model.
Just give some more information about what you'd like to achive… and what are you doing right now.
Maybe offer a small test, so others can reproduce the scenario. Therefor load up the model as well.
Looks like you forgot to call updateRenderState on something, causing the Text texture to bleed into your scene.
I use only boxes and quads no other spatials. I have no external models. It apears that when box intersects
with quad it may happen. I have added one line.
getRootNode().updateRenderState();
And it works. I can't see any letters and it is ok, because I don't have any textures yet and I want
to have blank quads and boxes.
So problem is solved. Thank you for fast answer.
SOLVED.