The Letters of "Ikhfa'"

To facilitate memorizing the letters 'ikhfa', they were collected in the poetic lines:

صِفْ ذَا ثَنَا كَمْ جَادَ شَخْصٌ قَدْ سَمَا

دُمْ طَيِّبًا زِدْ فِي تُقَي ضَعْ ظَالِمًا