In the morning of 7/4/1991, when the sheikh teacher tapped his right hand over his left hand to warn my colleague, who was reading from the Holy Quran (because he missed a specific tajweed rule during the recitation), the following idea occurred to me:
Why doesn’t the letter subject to the tajweed rule show itself using a specific color instead of waiting for the teacher’s hand to point out the location of the tajweed rule, and the color tone shall indicate the time of this rule?. So that the tajweed will be written on the Ottoman calligraphy itself, as is the case with the diacritic and punctuation on the letter, after it was only auditory…
Thus the necessity was the mother of invention.

Dr. Eng. Subhi Taha