iRegion3

auto a = fRegion1(1,5);
auto b = fRegion1(2,5);
assert( a.overlap(b) == b.overlap(a) );
assert( a.overlap(b) == fRegion1(2,4) );

assert( a.overlapLocal(b) == fRegion1(2,3) );

auto a = fRegion1(1,2);
auto b = fRegion1(4,2);
assert( a.expand(b) = fRegion1(1,5) );

alias Region!(5,float) MSR; // MultiSpaceRegtion
alias MSR.ptype msrvec;
auto a = MSR( msrvec(1,0,3,4,3), msrvec(3,2,4,8,4) );
assert( msrvec(2,1,4,5,5) in a );