[NTG-context] displaying lines of formulas one by one

Dear all, I'd like to show the following formula line by line in a presentation, For example, \startformula\startalign \NC T(4) \NC = T(3) + 4 \NR \NC \NC= T(2) + 3 + 4 \NR \NC \NC= T(1) + 2 + 3 + 4 \NR \NC \NC= 1 + 2 + 3 + 4 = 10 \NR \stopalign\stopformula I tried to use \StartSteps and \StopSteps but not succeed. \starttext \usemodule[pre-60] \StartSteps \startformula\startalign \NC T(4) \NC = T(3) + 4 \NR\FlushStep %(nor \FlushStep\NR) \NC \NC= T(2) + 3 + 4 \NR\FlushStep \NC \NC= T(1) + 2 + 3 + 4 \NR\FlushStep \NC \NC= 1 + 2 + 3 + 4 = 10 \NR\FlushStep \stopalign\stopformula \StopSteps \stoptext Is there a way to do so? Thank you. Best regards, Dalyoung