a typewriter that belonged to the Yiddish author Isaac Bashevis Singer . Typewriters built directly for Yiddish include the same four additional characters in different positions, as can be seen on another typewriter that belonged to Singer . The salient difference between the two designs is that each key on the Yiddish typewriter produces one character only, available in two different sizes through shifting. As a result of the widespread practice of writing Yiddish on Hebrew keyboards and other legacy effects of the variant digraph forms on both modified Hebrew and native Yiddish typewriters, when Yiddish text is entered from a computer keyboard with single-key digraphs, many people nonetheless type the digraphs as two-key combinations, giving the corresponding two-letter sequences (tsvey vovn U+05D5 U+05D5; vov yud U+05D5 U+05D9; tsvey yudn U+05D9 U+05D9). Although ligatures can be appropriate in monospaced typewritten text, other than in the smallest type sizes they rarely appear in proportional typesetting, where the elements of a digraph are normally letterspaced as individual characters (illustrated in Max Weinreich's name in the facsimile text in the preceding section). It may be of further interest to note that a useful, albeit highly colloquial, test of whether digraphs are regarded as single or double characters is provided by the way they appear in crossword puzzles. In Yiddish, each element of a digraph is written in its own square (and the same practice applies to other word games where letters are allocated to positions of fixed width in a regular array). The pointed digraph pasekh tsvey yudn can also be typed in different ways. The one is simply to enter a precomposed pasekh tsvey yudn, which is both displayed and stored as a single character ײַ (U+FB1F). The second option is to enter the tsvey yudn ligature as a base character and then to enter a combining pasekh for display together with it. Although appearing to be a single character ײַ, it is stored digitally as two separate characters (U+05F2 U+05B7). These two forms can only be directly entered from a keyboard on which the ligature appears. As a result, a practice is developing where pasekh tsvey yudn are indicated by enclosing a pasekh between the elements of a two-character digraph. The pasekh aligns correctly only with the first yud (subject to conditions described in the next section) but the display is tolerably that of a fully marked digraph יַי and in