Piying or Pieing: How To spell?

The word Piying is misspelled against Pieing, which is present continuous of "Pi"

Word contains consecutive vowels 'EI' in between alphabets pi & ng is misspelled as 'YI'
Wrong Spelling:  pi-yi-ng 
Correct Spelling:  pi-ei-ng 
Find more wrongly spelled words of Pieing to spell it well.