spaces

	foo bar		SPACE
				Depends on font, typically 1/4 em, often adjusted
	foo bar		NO-BREAK SPACE
				As a space, but often not adjusted
	foo᠎bar		MONGOLIAN VOWEL SEPARATOR
				No width
	foo bar		EN QUAD
				1 en (= 1/2 em)
	foo bar		EM QUAD
				1 em (nominally, the height of the font)
	foo bar		EN SPACE
				1 en (= 1/2 em)
	foo bar		EM SPACE
				1 em
	foo bar		THREE-PER-EM SPACE
				1/3 em
	foo bar		FOUR-PER-EM SPACE
				1/4 em
	foo bar		SIX-PER-EM SPACE
				1/6 em
	foo bar		FIGURE SPACE
				“Tabular width”, the width of digits
	foo bar		PUNCTUATION SPACE
				The width of a period “.”
	foo bar		THIN SPACE
				1/5 em (or sometimes 1/6 em)
	foo bar		HAIR SPACE
				Narrower than THIN SPACE
	foo​bar		ZERO WIDTH SPACE
				Nominally no width, but may expand
	foo bar		NARROW NO-BREAK SPACE
				Narrower than NO-BREAK SPACE (or SPACE)
	foo bar		MEDIUM MATHEMATICAL SPACE
				4/18 em
	foo　bar		IDEOGRAPHIC SPACE
				The width of ideographic (CJK) characters.
	foobar		ZERO WIDTH NO-BREAK SPACE
				No width (the character is invisible)