function trans() {
let ss = SpreadsheetApp.getActiveSpreadsheet();
let shtIn = ss.getSheetByName("in");
let shtOut = ss.getSheetByName("out");
let responses = shtIn.getRange("B2:B4").getValues();
//responses is a 2d array that looks like this [[a],[b],[c]]
//first transpose it
let transResp = responses[0].map((resp,i)=>responses.map(r => r[i]))
//we now have [[a,b,c]]
//BUT this is still 2d array. the appendRow function needs a 1d array
//So... you can do one of two things...
//1. just use the first row
shtOut.appendRow(transResp[0])
//2. you can use array.flat()
shtOut.appendRow(transResp.flat())
//Clear the 'form'
shtIn.getRange("B2:B4").clearContent();
}