| understanding of concept | A | is high at time 1 | the students learned A before |
| understanding of concept | A | is high in time 2 and later | if the students consolidated that understanding by learning B or C in time 1 |
| understanding of concept | B | is high (any time) | if students just previously understood either A or C |
| understanding of concept | C | is high (any time) | if students just previously understood either A or B |
| understanding of concept | D | is high (any time) | if students just previously understood B or C |
| understanding of concept | F | is high at time 1 | if they already new E at time 0 |
| understanding of concept | F | is high in time 2 and later | if the students either already just understood E or they had just previously learned C and yet still remember A |
