Powershell - Create array of arrays for Google sheets append api - json

Question

I am tryign to use this google sheets append api to update values in bulk. I've used it the past for single rows updates and thats been fine , but i have a large data set I want to append in chunks. Using the
https://sheets.googleapis.com/v4/spreadsheets/$MYSHEETID/values/ExternallyExposed!A1%3AB10:append?insertDataOption=INSERT_ROWS&responseValueRenderOption=UNFORMATTED_VALUE&valueInputOption=RAW
Using the API explorer this is the expected JSON that google expects, note that Values is an array of arrays. Im having difficulty with the values array of arrays section. I cant seem to get it to just be
values : [ [a,b],[c,d],[e,f] ]
i just keep getting something like values : [a,b], values: [c,d]
{
"majorDimension": "ROWS",
"range": "ExternallyExposed!A1:B10",
"values": [
[
"a",
"b"
],
[
"e",
"f"
],
[
"g",
"h"
]
]
}
I've tried various things like
$x = #(
,#("a","b"),
,#("c","D"),
,#("e","F")
) | convertto-json does not produce the expected results.
or
$values= #()
$values+= [pscustomobject]#{
values = #(
"data"
"data"
)
}
gives me
{
"values": [
"data",
"data",
"data"
]
},
{
"values": [
"data",
"data",
"data"
]
}
]

Answer 1

I got help elsewhere, just posting the answer incase others have the same issue.
$values = ("a","b"),("c","d"),("e","f")
$build = [PSCustomObject]#{
'majorDimension' = 'ROWS'
'range' = 'ExternallyExposed!A1:B10'
'values' = $values
}
$json = $build | ConvertTo-Json
The values can also be built this way iterating though a loop.
foreach ($item in $items)
{
$values += ,("a","b")
}