Multiple techashim in the time of the midbar

Summary: Which then resolves the question of where the shoes in Yechezkel came from.

Post: Consider the following pasuk and midrash in Terumah:

5. ram skins dyed red, tachash skins, and acacia wood;

ה. וְעֹרֹת אֵילִם מְאָדָּמִים וְעֹרֹת תְּחָשִׁים וַעֲצֵי שִׁטִּים:

The Midrash Tanchuma says:

וזאת התרומה וגו', וערת אלים מאדמים ועורות תחשים רבי יהודה ורבי נחמיה
רבי יהודה אומר: 
חיה טהורה גדולה הייתה במדבר וקרן אחת היה לה במצחה, ובעורה ששה גוונים, ונטלו אותה ועשו ממנה יריעות.

ורבי נחמיה אומר: 
מעשה נסים הייתה, ולשעה שנבראת, בו בשעה נגנזה. 

ועורות תחשים 

למה? 
דכתיב: אורך היריעה האחת שלשים באמה. 

מי מביא לך יריעה של שלושים אמה? 
אלא מעשה נס, לשעה שנבראת נגנזה: 

"[A dispute between] Rabbi Yehuda and Rabbi Nechemia. 


Rabbi Yehuda says: A large kosher wild animal was there in the wilderness, and it had a single horn on its forehead, and in its hide was six colors. And they took it and made from it curtains.


And Rabbi Nechemia says: It was a miraculous occurrence, and it was created just for its time, and at that time, it was hidden away."


And skins of techashim? Why? For it is written: The length of each curtain was 30 cubits. Now who will bring you a 30 cubit curtain? Rather, it was a miraculous thing, and in the time it was created it was hidden away."

The bit about six colors in its hide is a riff on the Aramaic rendition of techashim as sasgevana, color from worms, and from there vermilion or sky-blue. And so he takes it instead as shesh + gevana. So too the gemara which understands it as sas, rejoices, + gevana, colors.

There is also a gemara about tachash in Shabbat 28b:

מאי הוי עלה דתחש שהיה בימי משה א"ר אלעא אמר רשב"ל אומר היה ר"מ תחש שהיה בימי משה בריה בפני עצמה היה ולא הכריעו בה חכמים אם מין חיה הוא אם מין בהמה הוא וקרן אחת היתה לו במצחו ולפי שעה נזדמן לו למשה ועשה ממנו משכן ונגנז מדקאמר קרן אחת היתה לו במצחו ש"מ טהור היה דא"ר יהודה שור שהקריב אדם הראשון קרן אחת היתה לו במצחו שנאמר (תהלים סט, לב)ותיטב לה' משור פר מקרין מפריס מקרין תרתי משמע אמר ר"נ בר יצחק מקרן כתיב וליפשוט מיניה דמין בהמה הוא כיון דאיכא קרש דמין חיה הוא ולית ליה אלא חדא קרן איכא למימר מין חיה הוא:

Or, in English:

What is our conclusion with respect to the tahash which existed in Moses' days? — Said R. Elai in the name of R. Simeon b. Lakish, R. Meir used to maintain, The tahash of Moses' day was a separate species, and the Sages could not decide whether it belonged to the genus of wild beasts or to the genus of domestic animals; and it had one horn in its forehead, and it came to Moses' hand [providentially] just for the occasion,¹²  and he made the [covering of the] Tabernacle, and then it was hidden. Now, since he says that it had one horn in its forehead, it follows that it was clean. For R. Judah said, The ox which Adam the first [man] sacrificed had one horn in its forehead, for it is said, and it shall please the Lord better than an ox, or a bullock that hath a horn [sic] and hoofs.¹³  But makrin¹⁴  implies two? — Said R. Nahman b. Isaac: Mi-keren¹⁵  is written.¹⁶  Then let us solve thence that it was a genus of domestic animal?¹⁷  — Since there is the keresh,¹⁸  which is a species of beast, and it has only one horn, one can say that it [the tahash] is a kind of wild beast.

This is parallel in that it also states that it came about lefi shaah.

Rav Chaim Kanievsky discusses this midrash, in Taama deKra. He cites the pasuk and Rabbi Nechemiah's position, and refers to the parallel in the gemara in Shabbos. Then, he continues:

"And it seems that several techashim were created, each one 30 cubits long, so that the Israelites could choose that which they wanted, and that is why it states עֹרֹת תְּחָשִׁים in the plural. And from the remainder of the left-over techashim the Israelites made from their hides sandals for their feet. And thus is resolved the question of the Re'em, that behold it states in Yechezkel 16, וָאַלְבִּישֵׁךְ רִקְמָה, וָאֶנְעֲלֵךְ תָּחַשׁ; וָאֶחְבְּשֵׁךְ בַּשֵּׁשׁ, וַאֲכַסֵּךְ מֶשִׁי. 'I clothed thee also with richly woven work, and shod thee with sealskin, and I wound fine linen about thy head, and covered thee with silk.' And it is explained in Yevamot 102b that this was speaking about actual, literal, sandals:

Rab Judah stated in the name of Rab: No halizah may be performed with a sandal that was sewn with flax,¹⁶  for it is said in Scripture, And I shod thee with tahash.¹⁷  Might it be suggested that [the skin of] a tahash¹⁸  is admissible¹⁹  but not any other material? — The mention of 'shoe' twice²⁰  indicates the inclusion [of all kinds of leather]. If the repeated mention of 'shoe' indicates the inclusion [of all kinds of leather] all other materials should also be included! — If that were so,²¹  for what purpose was the term tahash used?

And this that was stated that they were hidden away, this is only these that were created and left over, but that more than that, there was not in the land."