This is just a simple little twist on speaking activities. It resembles the mechanics of ultimate rock paper scissors / ultimate janken, wherein the loser of each match-up goes to the back of the winner, and they continue to find other match-ups, as one caterpillar or chain of people, until they get more and more people .
Except there isn't just one ultimate winner here, by the end of the time limit, there will be 2-5 different caterpillars or chains of people with the same answer.
It's flexible. Use any target sentence, but limit the number of possible own answers (in which students can personalize the sentence), to maybe 2-5 options only. This limits the chance of a person not finding anyone with the same answer, and feeling alienated/embarrassed. But you can also set expectations at the start of the activity that this isn't about winning or having the longest caterpillar or most number of people. They can think of it as a different way of doing a survey, and easily counting how many people have the same answer.
I specifically used this activity this week for:
ES 3年 Let's Try Textbook Unit 4: I like/I don't like.
(After doing other preliminary activities from the textbook)
We practiced the statement "Hello. I like ____."
Instruct all students to think of 1 color they like (As extra guide, you can ask them to get the color from their box of crayons).
They practice saying their own statement "I like green/white/etc."
Demonstrate with HRT, to show what will happen if you meet and have the same answer, and if different answer. (say goodbye)
You can set a time limit or check when most students have segregated into their caterpillars.
Then have them line up, and ask the whole class to count the number of people on one caterpillar.
How many red? one, two, three.... How many blue? (from Unit 3 of textbook)
(There will be colors with fewer students. Make sure to explain that it is not about having the most number of people, and it's okay if not everyone has the same likes.)
Then we did one more round: limiting the options to either cat or dog as animal they like.
Next week, we will do I don't like statements, again limiting the options they can choose from to only 2-5.