how.old                 Determine numeric age
lexis.age               Emphasize a certain age in Lexis grid
lexis.cohort            Emphasize a certain cohort in a Lexis grid
lexis.grid              Plot a Lexis grid
lexis.hmd               Fill Lexis triangles by HMD data
lexis.lifeline          Plot lifelines into a Lexis grid
lexis.year              Emphasize a certain year in Lexis grid.
lifelines_sample        Data for 300 random lifelines
prepare.hmd             Prepare HMD data for 'lexis.hmd()'
what.date               Determine the date a certain age is reached
