Hello everyone,
I recently came up with a pen-and-paper system for doing SRS that I think is pretty neat and is also fairly simple, once you understand how it works. It requires people to work in pairs. I’ve been having the students try it in an ESL class that I’m teaching.
Anyway, here’s the system.
To start, each student should have a piece of paper to make columns on. It would probably be a good idea to put the paper length-wise.
For each round, you should either give the students a certain amount of time or a certain amount of words that they need to have in the column for the round. You could do one round per day or more than one, or one every few days. A round is just one time of using the system.
For the first round, person A should ask person B a word in the L1 and person B should respond in the L2. Person A should write the word and the L2 definition in the first column. If person B responded incorrectly, person A should also write the word in the second column.
On round two, person A should go through columns 2 and 1 and ask person B all of the words that are in the columns. If person B gets any wrong, the words should be written in the next column, column 3. Then, person A should ask person B new words and write them down in column 2 until the time or word limit is reached. If person B gets any of the new words wrong, they should also be written in column 3.
One column should be added per round. However, the amount of columns that should be reviewed changes, with not every column being reviewed each round. The formula for this is that the person should review x number of columns, where x = sqrt(number_of_days_this_system_has_been_used), rounded up.
If x is a whole number before rounding, then all columns should be reviewed.
Hopefully some examples will help clarify things.
Round 1
Since this is the first day, there aren’t any words to review.
---------------------------------------------
| | | | | hi 你好 | hi 你好 |
| | | | | he 他 | you 你 |
| | | | | | me 我 |
| | | | | | he 他 |
| | | | | | |
| | | | | | |
| | | | | | |
----------------------------------------------
Here, they’ve studied the words “hi”, “you”, “me”, and “he”, and they got the words “hi” and “he” wrong, so those words were also written in column two.
Round 2
x = sqrt(2) = ~1.4
Always round x up, so x = 2. This means they should review two columns, starting from the left, so they should review columns 2 and 1.
They review all of the words in columns 2 and 1 and then write more words in column 2. Any words that they get wrong during the entire process should be written in column 3.
---------------------------------------------
| | | | he 他 | hi 你好 | hi 你好 |
| | | | mom 妈妈| he 他 | you 你 |
| | | | | mom 妈妈| me 我 |
| | | | | dad 爸爸| he 他 |
| | | | | | |
| | | | | | |
| | | | | | |
----------------------------------------------
Here, they reviewed “hi”, “he”, “you”, and “me” and got “he” wrong. They then studied two new words, “mom” and “dad”, and got “mom” wrong.
Day 3
x = sqrt(3) = ~1.7. Round up, so x = 2
x = 2, so they should review columns 3 and 2.
---------------------------------------------
| | | he 他 | he 他 | hi 你好 | hi 你好 |
| | | dad 爸爸| mom 妈妈| he 他 | you 你 |
| | | son 儿子| | mom 妈妈| me 我 |
| | | | | dad 爸爸| he 他 |
| | | | | | |
| | | | | | |
| | | | | | |
----------------------------------------------
Here, they one word from column 3 and one word from column 2 wrong and then learned the word “son”.
Anyway, one should continue like this. Here are how many columns should be reviewed each day/round:
Round 1: 0
Rounds 2-3: 2
Round 4: All columns
Rounds 5-8: 3
Round 9: All columns
Round 10-15: 4
Round 16: All columns
etc.
Not surprisingly, the rounds that you should review all columns correspond with numbers that are perfect squares
11 = 1
22 = 4
33=9
44=16
etc.
It may be kind of hard to see what’s happening from this example, but if I’ve done my math correctly, then basically each time they learn or review a word and get it correct, the review period for that word roughly doubles. If they get the word wrong, then the review period resets.
One of the cool things about this system is that it’s based on rounds instead of time, so if you miss a review period, you don’t have a huge backlog of items for you to review (although as you later review items that you normally would have reviewed earlier, you might get more wrong, of course).
I hope this helps some people. I think it’s a pretty neat system 
Tagging @pdao because I know he teaches ESL and tagging @DrewSSP, @Arete_Hime, @Hydroptere, and @sircemloud because I think they might be interested.