counter-clockwise, while those that are asymmetrical top-to-bottom, c-, k-, m-, n-, s-, y-, are rotated 180 degrees (a half turn). The lower front-vowel (-e) syllables are derived this way from the low back-vowel (a) syllables, and the high front-vowel (-i) syllables are derived this way from the higher back-vowel (-u) syllables. The symmetrical letter forms can be illustrated by arranging them into a diamond: {| | || ᐃ || || || || i || || | || ᐱ || || || || bi/pi || || | || ᑎ || || || || ti/di || |- | ᐊ || || ᐅ || || a || || o || | ᐸ || || ᐳ || || ba/pa || || bo/po || | ᑕ || || ᑐ || || ta/da || || to/do |- | || ᐁ || || || || e || || | || ᐯ || || || || be/pe || || | || ᑌ || || || || te/de || |} And the asymmetrical letter forms can be illustrated by arranging them into a square: {| | ᑭ || ᑫ || || gi/ki || ge/ke || | ᒋ || ᒉ || || ji/ci || je/ce || | ᒥ || ᒣ || || mi || me || | ᓂ || ᓀ || || ni || ne || | ᓯ || ᓭ || || si || se || | ᔨ || ᔦ || || yi || ye || |- | ᑲ || ᑯ || || ga/ka || go/ko || | ᒐ || ᒍ || || ja/ca || jo/co || | ᒪ || ᒧ || || ma || mo || | ᓇ || ᓄ || || na || no || | ᓴ || ᓱ || || sa || so || | ᔭ || ᔪ || || ya || yo || |} These forms are present in most syllabics scripts with sounds values that approach their Swampy Cree origins. For example, all scripts except the one for Blackfoot use the triangle for vowel-initial syllables. By 1841, when Evans cast the first movable type for syllabics, he found that he could not satisfactorily maintain the distinction between light and heavy typeface for short and long vowels. He instead filed across the raised lines of the type, leaving gaps in the printed letter for long vowels. This can be seen in early printings. Later still a dot diacritic, originally used for vowel length only in handwriting,