Per https://www.mediawiki.org/wiki/Wikidata_query_service/User_Manual#Search_within_box currently only the following are supported:
wikibase:cornerSouthWest The south-west corner of the box.
wikibase:cornerNorthEast The north-east corner of the box.
This feature request suggests to add the following:
wikibase:cornerSouthEast The south-east corner of the box.
wikibase:cornerNorthWest The north-west corner of the box.
Sample query, based on the current sample, should give comparable results:
#Schools between Winters and Ashrama (same as San Jose, CA and Sacramento, CA)
#defaultView:Map
SELECT * WHERE
{
wd:Q986857 wdt:P625 ?SJloc .
wd:Q2396418 wdt:P625 ?SCloc .
SERVICE wikibase:box {
?place wdt:P625 ?location .
bd:serviceParam wikibase:cornerNorthWest ?SJloc .
bd:serviceParam wikibase:cornerSouthEast ?SCloc .
}
?place wdt:P31/wdt:P279* wd:Q3914 .}