 The presence and absence of this matra can be important.For example, the letter ত "tô" and the numeral ৩ "3" are distinguishable only by the presence or absence of the "matra", as is the case between the consonant cluster ত্র "trô" and the independent vowel এ "e".The letter-forms also employ the concepts of letter-width and letter-height (the vertical space between the visible matra and an invisible baseline).