Transforming data in spreadsheet (Excel or Google Sheets) such that every N rows gets autofilled

Question

Lets say I have a spreadsheet as follows:

name	x1	x2	x3
a	4	8	9
b	5	2	6
c	7	3	1

And I want it in the format

name	var	value
a	x1	4
a	x2	8
a	x3	9
b	x1	5
b	x2	2
b	x3	6
c	x1	7
c	x2	3
c	x3	1

What is the best way to accomplish this in Google Sheets? Or am I better off just transforming the data in Python/R?

EDIT: Thanks everyone for the great solutions in spreadsheets. I found it simpler to just convert using Python, but I appreciate the newfound spreadsheet knowledge!

Answer 1

={"name","var","value";
index(split(flatten(A2:A4&"❄️"&B1:D1&"❄️"&B2:D4),"❄️"))}

Reference: Unpivot In Google Sheets