I used to think only a part of a spaceframe from the original ship remained in the TMP ship. I have come to believe in recent years, in acknowledgement of the close relationship between original and Phase II, and Phase II and TMP, that the TMP and original ship might be substantially the same, with only superficial upgrades but substantial technological improvements. In other words, we saw certain sets in TOS most of which are there in TMP though styled like TMP. And we saw certain sets in TMP most of which are there in TOS though styled like TOS. These just went unseen, as did most of both ships.