Rashi on Exodus 25:5/רש"י על שמות כ״ה:ה׳

1מאדמים RED — they were dyed red after having been tanned.

2תחשים TACHASH was a kind of wild beast. It existed only at that time (when Israel built the Tabernacle). It was multi-coloured and therefore it is translated in the Targum by ססגונה, and it is so translated because it delights (שָׂשׂ) and prides itself in its colours (גונא) (Shabbat 28; Midrash Tanchuma, Terumah 6).

3ועצי שטים AND SHITTIM WOOD — But from where did they get this in the wilderness? Rabbi Tanchuma explained it thus: Our father Jacob foresaw by the gift of the Holy Spirit that Israel would once build a Tabernacle in the wilderness: he therefore brought cedars to Egypt and planted them there, and bade his children take these with them when they would leave Egypt (Midrash Tanchuma, Terumah 9; cf. Bereishit Rabbah 94 and Rashi on Exodus 26:15).