concurring specially.
I concur fully in Divisions 1 and 3.1 concur in Division 2 in finding no error, because the evidence, if otherwise admissible, was not shown to have scientific validity. Harper v. State, 249 Ga. 519, 523 (1) (292 SE2d 389) (1982). I do not reach the other ground of exclusion, which is based on whether the evidence has a valid purpose. That is the question addressed in Jennette v. State, 197 Ga. App. 580, 581 (3) *450(398 SE2d 734) (1990), and Smith v. State, 247 Ga. 612 (277 SE2d 678) (1981).
Decided November 24, 1992. Clark & McLaughlin, Michael C. Clark, for appellant. Thomas C. Lawler III, District Attorney, Debra K. Turner, Assistant District Attorney, for appellee.