I have not been trying to make an April fool nor have I been trying to test anyone but been looking for some insight. If we look at the ’Bras spungs dkar chag, we would see that some of the texts recorded there are said to be in rdo par. The first possibility is as Dan has suggested it simply means “stone[block] print” (analogous to shing par “xylographic print”). But the question is whether this is indeed the case. I personally do not know and have never seen one. When Tibetan authors speak of rdo par, do they really mean stone-block print? Is such a practice/tradition known? The second possibility is the rdo par is simply a neo-Tibetanism for lithographic print? But I don’t know if this is the case. I also have no idea about Tibetan knowledge and practice of lithography. The third possibility is to consider the so-called rdo ’bum. The word rdo ’bum is quite ambiguous. One might assume that it is the larger Prajñāpāramitā scriptures carved on stones, but if we look at the expression ma ṇi rdo ’bum, it is apparently understood as a huge collection of stones upon which the syllabic mantra oṃ ma ṇi padme hūṃ. This may be the primarily meaning of rdo ’bum. But if we read http://ti.kbcmw.com/Html/KangBa/LiShi/14/12/Content_201412239177.html, we learn that indeed many texts from the bKa’ ’gyur and bsTan ’gyur (and even the entire bsTan ’gyur?) have been carved on stones. But I would assume that texts carved out in this way are never done in a mirror-image form and hence never be printed on a paper. So our initial question regarding what a rdo par may be still remains unanswered at least for me.