 Our hypothesis leads to an experimentally testable prediction that a system with both types of invariance detects the relative steepness even in spatio-temporal gradient stimuli such as waves .
<clarity>  Our hypothesis leads to an experimentally testable prediction that a system with both types of invariance detects the relative steepness even in spatio-temporal gradient stimuli such as waves .
 Our hypothesis leads to an experimentally testable prediction that a system with the invariance detects relative steepness even in spatio-temporal gradient stimuli such as waves .