Calligraphy: What pen are these two words written with?

It looks like a calligraphy pen or an art pen or something.

But I can also write this similar effect with casual bamboo or sawdust.

From the strokes in the upper right corner of the word "Bao", we can see the traces of using a pen.

There are many calligraphy pens or art written tests that are processed by ourselves.

Therefore, the writing effect of strokes and conventional products will be different.