'new kind thing of object': ok
'new kind device of thing': ok
'new kind vehicle of thing': ok
'new unit length': ok
'number <= number?': true
'number <= real number?': false
'value <= number?': false
'object <= text?': false
'object <= thing?': false
'thing <= object?': true
'device <= thing?': true
'device <= object?': true
'list of devices <= thing?': false
'list of devices <= list of things?': true