<style>
.container {
  width: 200px;
  height: 100px;
  background-color: red;
  overflow: hidden;
}

.intrusive_float {
  background-color: green;
  height: 100px;
}

.containing_block {
  height: 100px;
  width: 100px;
  background-color: cyan;
}

.oveflowing_float {
  width: 150px;
  height: 100px;
  background-color: green;
}
</style>
<div class=container>
  <div class=intrusive_float style="float: right; width: 30px;"></div>
  <div class=intrusive_float style="float: right; width: 20px;"></div>
  <div class=containing_block>
    <div class=oveflowing_float style="float: left"></div>
    PASS if no red.
  </div>
</div>
<div class=container>
  <div class=intrusive_float style="float: left; width: 30px;"></div>
  <div class=intrusive_float style="float: right; width: 20px;"></div>
  <div class=containing_block>
    <div class=oveflowing_float style="float: left; position: relative; top: -100px; left: 30px;"></div>
    PASS if no red.
  </div>
</div>
<div class=container>
  <div class=intrusive_float style="float: left; width: 30px;"></div>
  <div class=intrusive_float style="float: left; width: 20px;"></div>
  <div class=containing_block>
    <div class=oveflowing_float style="float: left; position: relative; top: -100px; left: 50px;"></div>
    PASS if no red.
  </div>
</div>
<div class=container>
  <div class=intrusive_float style="float: left; width: 30px;"></div>
  <div class=intrusive_float style="float: left; width: 20px;"></div>
  <div class=containing_block style="margin-left: 100px">
    <div class=oveflowing_float style="float: right;"></div>
    PASS if no red.
  </div>
</div>